+//
+// Enumerable.cs
+//
+// Authors:
+// Marek Safar (marek.safar@gmail.com)
+// Antonello Provenzano <antonello@deveel.com>
+// Alejandro Serrano "Serras" (trupill@yahoo.es)
+// Jb Evain (jbevain@novell.com)
+//
+// Copyright (C) 2007 Novell, Inc (http://www.novell.com)
+//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
-//
+//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
-//
+//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
-// Authors:
-// Marek Safar (marek.safar@gmail.com)
-// Antonello Provenzano <antonello@deveel.com>
-// Alejandro Serrano "Serras" (trupill@yahoo.es)
-//
+
+// precious: http://www.hookedonlinq.com
using System;
using System.Collections;
{
public static class Enumerable
{
+ enum Fallback {
+ Default,
+ Throw
+ }
+
+ class PredicateOf<T> {
+ public static readonly Func<T, bool> Always = (t) => true;
+ }
+
+ class Function<T> {
+ public static readonly Func<T, T> Identity = (t) => t;
+ }
+
#region Aggregate
+
public static TSource Aggregate<TSource> (this IEnumerable<TSource> source, Func<TSource, TSource, TSource> func)
{
- if (source == null)
- throw new ArgumentNullException ("source");
- if (func == null)
- throw new ArgumentNullException ("func");
+ Check.SourceAndFunc (source, func);
- // custom foreach so that we can efficiently throw an exception
+ // custom foreach so that we can efficiently throw an exception
// if zero elements and treat the first element differently
- using (IEnumerator<TSource> enumerator = source.GetEnumerator ()) {
+ using (var enumerator = source.GetEnumerator ()) {
if (!enumerator.MoveNext ())
throw new InvalidOperationException ("No elements in source list");
}
}
-
public static TAccumulate Aggregate<TSource, TAccumulate> (this IEnumerable<TSource> source,
TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> func)
{
- if (source == null || func == null)
- throw new ArgumentNullException ();
+ Check.SourceAndFunc (source, func);
TAccumulate folded = seed;
foreach (TSource element in source)
folded = func (folded, element);
+
return folded;
}
-
public static TResult Aggregate<TSource, TAccumulate, TResult> (this IEnumerable<TSource> source, TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> func, Func<TAccumulate, TResult> resultSelector)
{
- if (source == null)
- throw new ArgumentNullException ("source");
- if (func == null)
- throw new ArgumentNullException ("func");
+ Check.SourceAndFunc (source, func);
if (resultSelector == null)
throw new ArgumentNullException ("resultSelector");
- TAccumulate result = seed;
- foreach (TSource e in source)
+ var result = seed;
+ foreach (var e in source)
result = func (result, e);
+
return resultSelector (result);
}
+
#endregion
#region All
+
public static bool All<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
- foreach (TSource element in source)
+ foreach (var element in source)
if (!predicate (element))
return false;
+
return true;
}
+
#endregion
#region Any
+
public static bool Any<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- foreach (TSource element in source)
- return true;
- return false;
- }
+ var collection = source as ICollection<TSource>;
+ if (collection != null)
+ return collection.Count > 0;
+ using (var enumerator = source.GetEnumerator ())
+ return enumerator.MoveNext ();
+ }
public static bool Any<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
foreach (TSource element in source)
if (predicate (element))
return true;
+
return false;
}
+
#endregion
#region AsEnumerable
+
public static IEnumerable<TSource> AsEnumerable<TSource> (this IEnumerable<TSource> source)
{
return source;
}
+
#endregion
#region Average
+
public static double Average (this IEnumerable<int> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- long sum = 0;
- long counter = 0;
- foreach (int element in source) {
- sum += element;
- counter++;
- }
-
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return (double) sum / (double) counter;
+ return Average<int, long, double> (source, (a, b) => a + b, (a, b) => (double) a / (double) b);
}
+ public static double Average (this IEnumerable<long> source)
+ {
+ return Average<long, long, double> (source, (a, b) => a + b, (a, b) => (double) a / (double) b);
+ }
- public static double? Average (this IEnumerable<int?> source)
+ public static double Average (this IEnumerable<double> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ return Average<double, double, double> (source, (a, b) => a + b, (a, b) => a / b);
+ }
- bool onlyNull = true;
- long sum = 0;
- long counter = 0;
- foreach (int? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (double?) sum / (double?) counter);
+ public static float Average (this IEnumerable<float> source)
+ {
+ return Average<float, double, float> (source, (a, b) => a + b, (a, b) => (float) a / (float) b);
}
+ public static decimal Average (this IEnumerable<decimal> source)
+ {
+ return Average<decimal, decimal, decimal> (source, (a, b) => a + b, (a, b) => a / b);
+ }
- public static double Average (this IEnumerable<long> source)
+ static TResult Average<TElement, TAggregate, TResult> (this IEnumerable<TElement> source,
+ Func<TAggregate, TElement, TAggregate> func, Func<TAggregate, long, TResult> result)
+ where TElement : struct
+ where TAggregate : struct
+ where TResult : struct
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- long sum = 0;
+ var total = default (TAggregate);
long counter = 0;
- foreach (long element in source) {
- sum += element;
- counter++;
+ foreach (var element in source) {
+ total = func (total, element);
+ ++counter;
}
if (counter == 0)
throw new InvalidOperationException ();
- else
- return (double) sum / (double) counter;
- }
+ return result (total, counter);
+ }
- public static double? Average (this IEnumerable<long?> source)
+ static TResult? AverageNullable<TElement, TAggregate, TResult> (this IEnumerable<TElement?> source,
+ Func<TAggregate, TElement, TAggregate> func, Func<TAggregate, long, TResult> result)
+ where TElement : struct
+ where TAggregate : struct
+ where TResult : struct
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- bool onlyNull = true;
- long sum = 0;
+ var total = default (TAggregate);
long counter = 0;
- foreach (long? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (double?) sum / (double?) counter);
- }
-
-
- public static double Average (this IEnumerable<double> source)
- {
- if (source == null)
- throw new ArgumentNullException ();
+ foreach (var element in source) {
+ if (!element.HasValue)
+ continue;
- double sum = 0;
- double counter = 0;
- foreach (double element in source) {
- sum += element;
+ total = func (total, element.Value);
counter++;
}
if (counter == 0)
- throw new InvalidOperationException ();
- else
- return sum / counter;
- }
+ return null;
+ return new TResult? (result (total, counter));
+ }
- public static double? Average (this IEnumerable<double?> source)
+ public static double? Average (this IEnumerable<int?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- double sum = 0;
- double counter = 0;
- foreach (double? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (double?) (sum / counter));
- }
+ Check.Source (source);
+ return source.AverageNullable<int, long, double> ((a, b) => a + b, (a, b) => (double) a / (double) b);
+ }
- public static decimal Average (this IEnumerable<decimal> source)
+ public static double? Average (this IEnumerable<long?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- decimal sum = 0;
- decimal counter = 0;
- foreach (decimal element in source) {
- sum += element;
- counter++;
- }
+ Check.Source (source);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return sum / counter;
+ return source.AverageNullable<long, long, double> ((a, b) => a + b, (a, b) => (double) a / b);
}
+ public static double? Average (this IEnumerable<double?> source)
+ {
+ Check.Source (source);
+
+ return source.AverageNullable<double, double, double> ((a, b) => a + b, (a, b) => a / b);
+ }
public static decimal? Average (this IEnumerable<decimal?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- decimal sum = 0;
- decimal counter = 0;
- foreach (decimal? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (decimal?) (sum / counter));
+ Check.Source (source);
+
+ return source.AverageNullable<decimal, decimal, decimal> ((a, b) => a + b, (a, b) => a / b);
}
+ public static float? Average (this IEnumerable<float?> source)
+ {
+ Check.Source (source);
+
+ return source.AverageNullable<float, double, float> ((a, b) => a + b, (a, b) => (float) a / (float) b);
+ }
public static double Average<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- long sum = 0;
- long counter = 0;
- foreach (TSource item in source) {
- sum += selector (item);
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return (double) sum / (double) counter;
+ return source.Select (selector).Average<int, long, double> ((a, b) => a + b, (a, b) => (double) a / (double) b);
}
-
public static double? Average<TSource> (this IEnumerable<TSource> source, Func<TSource, int?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- long sum = 0;
- long counter = 0;
- foreach (TSource item in source) {
- int? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (double?) sum / (double?) counter);
+ return source.Select (selector).AverageNullable<int, long, double> ((a, b) => a + b, (a, b) => (double) a / (double) b);
}
-
public static double Average<TSource> (this IEnumerable<TSource> source, Func<TSource, long> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- long sum = 0;
- long counter = 0;
- foreach (TSource item in source) {
- sum += selector (item);
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return (double) sum / (double) counter;
+ return source.Select (selector).Average<long, long, double> ((a, b) => a + b, (a, b) => (double) a / (double) b);
}
-
public static double? Average<TSource> (this IEnumerable<TSource> source, Func<TSource, long?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- long sum = 0;
- long counter = 0;
- foreach (TSource item in source) {
- long? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (double?) sum / (double?) counter);
+ return source.Select (selector).AverageNullable<long, long, double> ((a, b) => a + b, (a, b) => (double) a / (double) b);
}
-
public static double Average<TSource> (this IEnumerable<TSource> source, Func<TSource, double> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- double sum = 0;
- double counter = 0;
- foreach (TSource item in source) {
- sum += selector (item);
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return sum / counter;
+ return source.Select (selector).Average<double, double, double> ((a, b) => a + b, (a, b) => a / b);
}
-
public static double? Average<TSource> (this IEnumerable<TSource> source, Func<TSource, double?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- double sum = 0;
- double counter = 0;
- foreach (TSource item in source) {
- double? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (double?) (sum / counter));
+ return source.Select (selector).AverageNullable<double, double, double> ((a, b) => a + b, (a, b) => a / b);
}
-
- public static decimal Average<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal> selector)
+ public static float Average<TSource> (this IEnumerable<TSource> source, Func<TSource, float> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- decimal sum = 0;
- decimal counter = 0;
- foreach (TSource item in source) {
- sum += selector (item);
- counter++;
- }
+ return source.Select (selector).Average<float, double, float> ((a, b) => a + b, (a, b) => (float) a / (float) b);
+ }
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return sum / counter;
+ public static float? Average<TSource> (this IEnumerable<TSource> source, Func<TSource, float?> selector)
+ {
+ Check.SourceAndSelector (source, selector);
+
+ return source.Select (selector).AverageNullable<float, double, float> ((a, b) => a + b, (a, b) => (float) a / (float) b);
}
+ public static decimal Average<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal> selector)
+ {
+ Check.SourceAndSelector (source, selector);
+
+ return source.Select (selector).Average<decimal, decimal, decimal> ((a, b) => a + b, (a, b) => a / b);
+ }
public static decimal? Average<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- decimal sum = 0;
- decimal counter = 0;
- foreach (TSource item in source) {
- decimal? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- sum += element.Value;
- counter++;
- }
- }
- return (onlyNull ? null : (decimal?) (sum / counter));
+ return source.Select (selector).AverageNullable<decimal, decimal, decimal> ((a, b) => a + b, (a, b) => a / b);
}
+
#endregion
#region Cast
+
public static IEnumerable<TResult> Cast<TResult> (this IEnumerable source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- foreach (object element in source)
- yield return (TResult) element;
+ return CreateCastIterator<TResult> (source);
+ }
+
+ static IEnumerable<TResult> CreateCastIterator<TResult> (IEnumerable source)
+ {
+ foreach (TResult element in source)
+ yield return element;
}
+
#endregion
#region Concat
+
public static IEnumerable<TSource> Concat<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second)
{
- if (first == null || second == null)
- throw new ArgumentNullException ();
+ Check.FirstAndSecond (first, second);
+
+ return CreateConcatIterator (first, second);
+ }
+ static IEnumerable<TSource> CreateConcatIterator<TSource> (IEnumerable<TSource> first, IEnumerable<TSource> second)
+ {
foreach (TSource element in first)
yield return element;
foreach (TSource element in second)
public static bool Contains<TSource> (this IEnumerable<TSource> source, TSource value)
{
- ICollection<TSource> collection = source as ICollection<TSource>;
+ var collection = source as ICollection<TSource>;
if (collection != null)
return collection.Contains (value);
return Contains<TSource> (source, value, null);
}
-
public static bool Contains<TSource> (this IEnumerable<TSource> source, TSource value, IEqualityComparer<TSource> comparer)
{
- if (source == null)
- throw new ArgumentNullException ("source");
+ Check.Source (source);
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
- foreach (TSource e in source) {
- if (comparer.Equals (e, value))
+ foreach (var element in source)
+ if (comparer.Equals (element, value))
return true;
- }
return false;
}
#endregion
#region Count
+
public static int Count<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- ICollection<TSource> collection = source as ICollection<TSource>;
+ var collection = source as ICollection<TSource>;
if (collection != null)
return collection.Count;
int counter = 0;
- foreach (TSource element in source)
- counter++;
+ using (var enumerator = source.GetEnumerator ())
+ while (enumerator.MoveNext ())
+ counter++;
+
return counter;
}
public static int Count<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
int counter = 0;
- foreach (TSource element in source)
+ foreach (var element in source)
if (selector (element))
counter++;
return counter;
}
+
#endregion
#region DefaultIfEmpty
public static IEnumerable<TSource> DefaultIfEmpty<TSource> (this IEnumerable<TSource> source, TSource defaultValue)
{
- if (source == null)
- throw new ArgumentNullException ("source");
+ Check.Source (source);
+
+ return CreateDefaultIfEmptyIterator (source, defaultValue);
+ }
- bool noYield = true;
+ static IEnumerable<TSource> CreateDefaultIfEmptyIterator<TSource> (IEnumerable<TSource> source, TSource defaultValue)
+ {
+ bool empty = true;
foreach (TSource item in source) {
- noYield = false;
+ empty = false;
yield return item;
}
- if (noYield)
+ if (empty)
yield return defaultValue;
}
public static IEnumerable<TSource> Distinct<TSource> (this IEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
- List<TSource> items = new List<TSource> (); // TODO: use a HashSet here
- foreach (TSource element in source) {
- if (!Contains (items, element, comparer)) {
+ return CreateDistinctIterator (source, comparer);
+ }
+
+ static IEnumerable<TSource> CreateDistinctIterator<TSource> (IEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
+ {
+ var items = new HashSet<TSource> (comparer);
+ foreach (var element in source) {
+ if (! items.Contains (element)) {
items.Add (element);
yield return element;
}
}
}
+
#endregion
#region ElementAt
+ static TSource ElementAt<TSource> (this IEnumerable<TSource> source, int index, Fallback fallback)
+ {
+ long counter = 0L;
+
+ foreach (var element in source) {
+ if (index == counter++)
+ return element;
+ }
+
+ if (fallback == Fallback.Throw)
+ throw new ArgumentOutOfRangeException ();
+
+ return default (TSource);
+ }
+
public static TSource ElementAt<TSource> (this IEnumerable<TSource> source, int index)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+
if (index < 0)
throw new ArgumentOutOfRangeException ();
- IList<TSource> list = source as IList<TSource>;
+ var list = source as IList<TSource>;
if (list != null)
return list [index];
- int counter = 0;
- foreach (TSource element in source) {
- if (counter == index)
- return element;
- counter++;
- }
-
- throw new ArgumentOutOfRangeException ();
+ return source.ElementAt (index, Fallback.Throw);
}
#endregion
public static TSource ElementAtOrDefault<TSource> (this IEnumerable<TSource> source, int index)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+
if (index < 0)
return default (TSource);
- IList<TSource> list = source as IList<TSource>;
+ var list = source as IList<TSource>;
if (list != null)
return index < list.Count ? list [index] : default (TSource);
- int counter = 0;
- foreach (TSource element in source) {
- if (counter == index)
- return element;
- counter++;
- }
-
- return default (TSource);
+ return source.ElementAt (index, Fallback.Default);
}
#endregion
#region Empty
+
public static IEnumerable<TResult> Empty<TResult> ()
{
- return new List<TResult> ();
+ return new TResult [0];
}
+
#endregion
#region Except
public static IEnumerable<TSource> Except<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
{
- if (first == null || second == null)
- throw new ArgumentNullException ();
+ Check.FirstAndSecond (first, second);
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
- List<TSource> items = new List<TSource> (Distinct (second));
- foreach (TSource element in first) {
- if (!Contains (items, element, comparer))
+ return CreateExceptIterator (first, second, comparer);
+ }
+
+ static IEnumerable<TSource> CreateExceptIterator<TSource> (IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
+ {
+ var items = new HashSet<TSource> (second, comparer);
+ foreach (var element in first) {
+ if (!items.Contains (element, comparer))
yield return element;
}
}
#region First
- public static TSource First<TSource> (this IEnumerable<TSource> source)
+ static TSource First<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate, Fallback fallback)
{
- if (source == null)
- throw new ArgumentNullException ();
+ foreach (var element in source)
+ if (predicate (element))
+ return element;
- foreach (TSource element in source)
- return element;
+ if (fallback == Fallback.Throw)
+ throw new InvalidOperationException ();
- throw new InvalidOperationException ();
+ return default (TSource);
}
-
- public static TSource First<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ public static TSource First<TSource> (this IEnumerable<TSource> source)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- foreach (TSource element in source) {
- if (predicate (element))
- return element;
+ var list = source as IList<TSource>;
+ if (list != null) {
+ if (list.Count != 0)
+ return list [0];
+
+ throw new InvalidOperationException ();
+ } else {
+ using (var enumerator = source.GetEnumerator ()) {
+ if (enumerator.MoveNext ())
+ return enumerator.Current;
+ }
}
throw new InvalidOperationException ();
}
+ public static TSource First<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ {
+ Check.SourceAndPredicate (source, predicate);
+
+ return source.First (predicate, Fallback.Throw);
+ }
+
#endregion
#region FirstOrDefault
public static TSource FirstOrDefault<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- foreach (TSource element in source)
- return element;
-
- return default (TSource);
+ return source.First (PredicateOf<TSource>.Always, Fallback.Default);
}
-
public static TSource FirstOrDefault<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
- foreach (TSource element in source) {
- if (predicate (element))
- return element;
- }
-
- return default (TSource);
+ return source.First (predicate, Fallback.Default);
}
#endregion
return null;
}
-
public static IEnumerable<IGrouping<TKey, TSource>> GroupBy<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector)
{
return GroupBy<TSource, TKey> (source, keySelector, null);
}
-
public static IEnumerable<IGrouping<TKey, TSource>> GroupBy<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
{
- if (source == null || keySelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeySelector (source, keySelector);
+
+ return CreateGroupByIterator (source, keySelector, comparer);
+ }
+ static IEnumerable<IGrouping<TKey, TSource>> CreateGroupByIterator<TSource, TKey> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+ {
Dictionary<TKey, List<TSource>> groups = new Dictionary<TKey, List<TSource>> ();
List<TSource> nullList = new List<TSource> ();
int counter = 0;
}
}
-
public static IEnumerable<IGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector)
{
return GroupBy<TSource, TKey, TElement> (source, keySelector, elementSelector, null);
}
-
public static IEnumerable<IGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
{
- if (source == null || keySelector == null || elementSelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeyElementSelectors (source, keySelector, elementSelector);
Dictionary<TKey, List<TElement>> groups = new Dictionary<TKey, List<TElement>> ();
List<TElement> nullList = new List<TElement> ();
}
}
+ public static IEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector,
+ Func<TKey, IEnumerable<TElement>, TResult> resultSelector)
+ {
+ return GroupBy (source, keySelector, elementSelector, resultSelector, null);
+ }
+
+ public static IEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector,
+ Func<TKey, IEnumerable<TElement>, TResult> resultSelector,
+ IEqualityComparer<TKey> comparer)
+ {
+ IEnumerable<IGrouping<TKey, TElement>> groups = GroupBy<TSource, TKey, TElement> (
+ source, keySelector, elementSelector, comparer);
+
+ foreach (IGrouping<TKey, TElement> group in groups)
+ yield return resultSelector (group.Key, group);
+ }
+
+ public static IEnumerable<TResult> GroupBy<TSource, TKey, TResult> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector,
+ Func<TKey, IEnumerable<TSource>, TResult> resultSelector)
+ {
+ return GroupBy (source, keySelector, resultSelector, null);
+ }
+
+ public static IEnumerable<TResult> GroupBy<TSource, TKey, TResult> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector,
+ Func<TKey, IEnumerable<TSource>, TResult> resultSelector,
+ IEqualityComparer<TKey> comparer)
+ {
+ IEnumerable<IGrouping<TKey,TSource>> groups = GroupBy<TSource, TKey> (source, keySelector, comparer);
+
+ foreach (IGrouping<TKey, TSource> group in groups)
+ yield return resultSelector (group.Key, group);
+ }
+
#endregion
# region GroupJoin
Func<TInner, TKey> innerKeySelector, Func<TOuter, IEnumerable<TInner>, TResult> resultSelector,
IEqualityComparer<TKey> comparer)
{
- if (outer == null || inner == null || outerKeySelector == null ||
- innerKeySelector == null || resultSelector == null)
- throw new ArgumentNullException ();
+ Check.JoinSelectors (outer, inner, outerKeySelector, innerKeySelector, resultSelector);
if (comparer == null)
comparer = EqualityComparer<TKey>.Default;
- Lookup<TKey, TInner> innerKeys = ToLookup<TInner, TKey> (inner, innerKeySelector, comparer);
+ return CreateGroupJoinIterator (outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer);
+ }
+
+ static IEnumerable<TResult> CreateGroupJoinIterator<TOuter, TInner, TKey, TResult> (this IEnumerable<TOuter> outer,
+ IEnumerable<TInner> inner, Func<TOuter, TKey> outerKeySelector,
+ Func<TInner, TKey> innerKeySelector, Func<TOuter, IEnumerable<TInner>, TResult> resultSelector,
+ IEqualityComparer<TKey> comparer)
+ {
+ ILookup<TKey, TInner> innerKeys = ToLookup<TInner, TKey> (inner, innerKeySelector, comparer);
/*Dictionary<K, List<U>> innerKeys = new Dictionary<K, List<U>> ();
foreach (U element in inner)
{
yield return resultSelector (element, innerKeys [outerKey]);
else
yield return resultSelector (element, Empty<TInner> ());
- }
+ }
}
#endregion
public static IEnumerable<TSource> Intersect<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
{
- if (first == null || second == null)
- throw new ArgumentNullException ();
+ Check.FirstAndSecond (first, second);
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
- List<TSource> items = new List<TSource> (Distinct (first));
- foreach (TSource element in second) {
- if (Contains (items, element, comparer))
+ return CreateIntersectIterator (first, second, comparer);
+ }
+
+ static IEnumerable<TSource> CreateIntersectIterator<TSource> (IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
+ {
+ var items = new HashSet<TSource> (second, comparer);
+ foreach (TSource element in first) {
+ if (items.Remove (element))
yield return element;
}
}
IEnumerable<TInner> inner, Func<TOuter, TKey> outerKeySelector,
Func<TInner, TKey> innerKeySelector, Func<TOuter, TInner, TResult> resultSelector, IEqualityComparer<TKey> comparer)
{
- if (outer == null || inner == null || outerKeySelector == null ||
- innerKeySelector == null || resultSelector == null)
- throw new ArgumentNullException ();
+ Check.JoinSelectors (outer, inner, outerKeySelector, innerKeySelector, resultSelector);
if (comparer == null)
comparer = EqualityComparer<TKey>.Default;
- Lookup<TKey, TInner> innerKeys = ToLookup<TInner, TKey> (inner, innerKeySelector, comparer);
+ return CreateJoinIterator (outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer);
+ }
+
+ static IEnumerable<TResult> CreateJoinIterator<TOuter, TInner, TKey, TResult> (this IEnumerable<TOuter> outer,
+ IEnumerable<TInner> inner, Func<TOuter, TKey> outerKeySelector,
+ Func<TInner, TKey> innerKeySelector, Func<TOuter, TInner, TResult> resultSelector, IEqualityComparer<TKey> comparer)
+ {
+ ILookup<TKey, TInner> innerKeys = ToLookup<TInner, TKey> (inner, innerKeySelector, comparer);
/*Dictionary<K, List<U>> innerKeys = new Dictionary<K, List<U>> ();
foreach (U element in inner)
{
IEnumerable<TInner> inner, Func<TOuter, TKey> outerKeySelector,
Func<TInner, TKey> innerKeySelector, Func<TOuter, TInner, TResult> resultSelector)
{
- return Join<TOuter, TInner, TKey, TResult> (outer, inner, outerKeySelector, innerKeySelector, resultSelector, null);
+ return outer.Join (inner, outerKeySelector, innerKeySelector, resultSelector, null);
}
- # endregion
+
+ #endregion
#region Last
- public static TSource Last<TSource> (this IEnumerable<TSource> source)
+ static TSource Last<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate, Fallback fallback)
{
- if (source == null)
- throw new ArgumentNullException ();
+ var empty = true;
+ var item = default (TSource);
- bool noElements = true;
- TSource lastElement = default (TSource);
- foreach (TSource element in source) {
- if (noElements) noElements = false;
- lastElement = element;
+ foreach (var element in source) {
+ if (!predicate (element))
+ continue;
+
+ item = element;
+ empty = false;
}
- if (!noElements)
- return lastElement;
- else
+ if (!empty)
+ return item;
+
+ if (fallback == Fallback.Throw)
throw new InvalidOperationException ();
+
+ return item;
}
- public static TSource Last<TSource> (this IEnumerable<TSource> source,
- Func<TSource, bool> predicate)
+ public static TSource Last<TSource> (this IEnumerable<TSource> source)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
-
- bool noElements = true;
- TSource lastElement = default (TSource);
- foreach (TSource element in source) {
- if (predicate (element)) {
- if (noElements) noElements = false;
- lastElement = element;
- }
- }
+ Check.Source (source);
- if (!noElements)
- return lastElement;
- else
+ var collection = source as ICollection<TSource>;
+ if (collection != null && collection.Count == 0)
throw new InvalidOperationException ();
+
+ var list = source as IList<TSource>;
+ if (list != null)
+ return list [list.Count - 1];
+
+ return source.Last (PredicateOf<TSource>.Always, Fallback.Throw);
+ }
+
+ public static TSource Last<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ {
+ Check.SourceAndPredicate (source, predicate);
+
+ return source.Last (predicate, Fallback.Throw);
}
#endregion
public static TSource LastOrDefault<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- TSource lastElement = default (TSource);
- foreach (TSource element in source)
- lastElement = element;
+ var list = source as IList<TSource>;
+ if (list != null)
+ return list.Count > 0 ? list [list.Count - 1] : default (TSource);
- return lastElement;
+ return source.Last (PredicateOf<TSource>.Always, Fallback.Default);
}
- public static TSource LastOrDefault<TSource> (this IEnumerable<TSource> source,
- Func<TSource, bool> predicate)
+ public static TSource LastOrDefault<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
-
- TSource lastElement = default (TSource);
- foreach (TSource element in source) {
- if (predicate (element))
- lastElement = element;
- }
+ Check.SourceAndPredicate (source, predicate);
- return lastElement;
+ return source.Last (predicate, Fallback.Default);
}
#endregion
#region LongCount
+
public static long LongCount<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+
+#if !NET_2_1
+ var array = source as TSource [];
+ if (array != null)
+ return array.LongLength;
+#endif
long counter = 0;
- foreach (TSource element in source)
- counter++;
+ using (var enumerator = source.GetEnumerator ())
+ while (enumerator.MoveNext ())
+ counter++;
+
return counter;
}
-
public static long LongCount<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
long counter = 0;
foreach (TSource element in source)
public static int Max (this IEnumerable<int> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- int maximum = int.MinValue;
- int counter = 0;
- foreach (int element in source) {
- if (element > maximum)
- maximum = element;
- counter++;
- }
+ Check.Source (source);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
+ return Iterate (source, int.MinValue, (a, b) => Math.Max (a, b));
}
-
- public static int? Max (this IEnumerable<int?> source)
+ public static long Max (this IEnumerable<long> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- int? maximum = int.MinValue;
- foreach (int? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
+ Check.Source (source);
+
+ return Iterate (source, long.MinValue, (a, b) => Math.Max (a, b));
}
+ public static double Max (this IEnumerable<double> source)
+ {
+ Check.Source (source);
- public static long Max (this IEnumerable<long> source)
+ return Iterate (source, double.MinValue, (a, b) => Math.Max (a, b));
+ }
+
+ public static float Max (this IEnumerable<float> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- long maximum = long.MinValue;
- int counter = 0;
- foreach (long element in source) {
- if (element > maximum)
- maximum = element;
- counter++;
- }
+ return Iterate (source, float.MinValue, (a, b) => Math.Max (a, b));
+ }
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
+ public static decimal Max (this IEnumerable<decimal> source)
+ {
+ Check.Source (source);
+
+ return Iterate (source, decimal.MinValue, (a, b) => Math.Max (a, b));
}
+ public static int? Max (this IEnumerable<int?> source)
+ {
+ Check.Source (source);
+
+ return IterateNullable (source, (a, b) => Math.Max (a, b));
+ }
public static long? Max (this IEnumerable<long?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- long? maximum = long.MinValue;
- foreach (long? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
- }
+ Check.Source (source);
+ return IterateNullable (source, (a, b) => Math.Max (a, b));
+ }
- public static double Max (this IEnumerable<double> source)
+ public static double? Max (this IEnumerable<double?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- double maximum = double.MinValue;
- int counter = 0;
- foreach (double element in source) {
- if (element > maximum)
- maximum = element;
- counter++;
- }
+ Check.Source (source);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
+ return IterateNullable (source, (a, b) => Math.Max (a, b));
}
-
- public static double? Max (this IEnumerable<double?> source)
+ public static float? Max (this IEnumerable<float?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- double? maximum = double.MinValue;
- foreach (double? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
+ Check.Source (source);
+
+ return IterateNullable (source, (a, b) => Math.Max (a, b));
}
+ public static decimal? Max (this IEnumerable<decimal?> source)
+ {
+ Check.Source (source);
+
+ return IterateNullable (source, (a, b) => Math.Max (a, b));
+ }
- public static decimal Max (this IEnumerable<decimal> source)
+ static T? IterateNullable<T> (IEnumerable<T?> source, Func<T, T, T> selector) where T : struct
{
- if (source == null)
- throw new ArgumentNullException ();
+ bool empty = true;
+ T? value = null;
+ foreach (var element in source) {
+ if (!element.HasValue)
+ continue;
- decimal maximum = decimal.MinValue;
- int counter = 0;
- foreach (decimal element in source) {
- if (element > maximum)
- maximum = element;
- counter++;
+ if (!value.HasValue)
+ value = element.Value;
+ else
+ value = selector (element.Value, value.Value);
+
+ empty = false;
}
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
- }
+ if (empty)
+ return null;
+ return value;
+ }
- public static decimal? Max (this IEnumerable<decimal?> source)
+ static TRet? IterateNullable<TSource, TRet> (
+ IEnumerable<TSource> source,
+ Func<TSource, TRet?> source_selector,
+ Func<TRet?, TRet?, bool> selector) where TRet : struct
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- decimal? maximum = decimal.MinValue;
- foreach (decimal? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
+ bool empty = true;
+ TRet? value = null;
+ foreach (var element in source) {
+ TRet? item = source_selector (element);
+
+ if (!value.HasValue)
+ value = item;
+ else if (selector (item, value))
+ value = item;
+
+ empty = false;
}
- return (onlyNull ? null : maximum);
- }
+ if (empty)
+ return null;
+
+ return value;
+ }
public static TSource Max<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
bool notAssigned = true;
TSource maximum = default (TSource);
return maximum;
}
-
- public static int Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, int> selector)
+ public static int Max<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- int maximum = int.MinValue;
- int counter = 0;
- foreach (TSource item in source) {
- int element = selector (item);
- if (element > maximum)
- maximum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
+ return Iterate (source, int.MinValue, (a, b) => Math.Max (selector (a), b));
}
-
- public static int? Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, int?> selector)
+ public static long Max<TSource> (this IEnumerable<TSource> source, Func<TSource, long> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- int? maximum = int.MinValue;
- foreach (TSource item in source) {
- int? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
+ return Iterate (source, long.MinValue, (a, b) => Math.Max (selector (a), b));
}
-
- public static long Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, long> selector)
+ public static double Max<TSource> (this IEnumerable<TSource> source, Func<TSource, double> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- long maximum = long.MinValue;
- int counter = 0;
- foreach (TSource item in source) {
- long element = selector (item);
- if (element > maximum)
- maximum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
+ return Iterate (source, double.MinValue, (a, b) => Math.Max (selector (a), b));
}
-
- public static long? Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, long?> selector)
+ public static float Max<TSource> (this IEnumerable<TSource> source, Func<TSource, float> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- long? maximum = long.MinValue;
- foreach (TSource item in source) {
- long? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
+ return Iterate (source, float.MinValue, (a, b) => Math.Max (selector (a), b));
}
-
- public static double Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, double> selector)
+ public static decimal Max<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- double maximum = double.MinValue;
- int counter = 0;
- foreach (TSource item in source) {
- double element = selector (item);
- if (element > maximum)
- maximum = element;
- counter++;
+ return Iterate (source, decimal.MinValue, (a, b) => Math.Max (selector (a), b));
+ }
+
+ static U Iterate<T, U> (IEnumerable<T> source, U initValue, Func<T, U, U> selector)
+ {
+ bool empty = true;
+ foreach (var element in source) {
+ initValue = selector (element, initValue);
+ empty = false;
}
- if (counter == 0)
+ if (empty)
throw new InvalidOperationException ();
- else
- return maximum;
- }
+ return initValue;
+ }
- public static double? Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, double?> selector)
+ public static int? Max<TSource> (this IEnumerable<TSource> source, Func<TSource, int?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- double? maximum = double.MinValue;
- foreach (TSource item in source) {
- double? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
+ return IterateNullable (source, selector, (a, b) => a > b);
}
-
- public static decimal Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, decimal> selector)
+ public static long? Max<TSource> (this IEnumerable<TSource> source, Func<TSource, long?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- decimal maximum = decimal.MinValue;
- int counter = 0;
- foreach (TSource item in source) {
- decimal element = selector (item);
- if (element > maximum)
- maximum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return maximum;
+ return IterateNullable (source, selector, (a, b) => a > b);
}
+ public static double? Max<TSource> (this IEnumerable<TSource> source, Func<TSource, double?> selector)
+ {
+ Check.SourceAndSelector (source, selector);
- public static decimal? Max<TSource> (this IEnumerable<TSource> source,
- Func<TSource, decimal?> selector)
+ return IterateNullable (source, selector, (a, b) => a > b);
+ }
+
+ public static float? Max<TSource> (this IEnumerable<TSource> source, Func<TSource, float?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- decimal? maximum = decimal.MinValue;
- foreach (TSource item in source) {
- decimal? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element > maximum)
- maximum = element;
- }
- }
- return (onlyNull ? null : maximum);
+ return IterateNullable (source, selector, (a, b) => a > b);
}
+ public static decimal? Max<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal?> selector)
+ {
+ Check.SourceAndSelector (source, selector);
- public static TResult Max<TSource, TResult> (this IEnumerable<TSource> source,
- Func<TSource, TResult> selector)
+ return IterateNullable (source, selector, (a, b) => a > b);
+ }
+
+ public static TResult Max<TSource, TResult> (this IEnumerable<TSource> source, Func<TSource, TResult> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
bool notAssigned = true;
TResult maximum = default (TResult);
public static int Min (this IEnumerable<int> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- int minimum = int.MaxValue;
- int counter = 0;
- foreach (int element in source) {
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ Check.Source (source);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return Iterate (source, int.MaxValue, (a, b) => Math.Min (a, b));
}
-
- public static int? Min (this IEnumerable<int?> source)
+ public static long Min (this IEnumerable<long> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- int? minimum = int.MaxValue;
- foreach (int? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
+ Check.Source (source);
+
+ return Iterate (source, long.MaxValue, (a, b) => Math.Min (a, b));
}
- public static long Min (this IEnumerable<long> source)
+ public static double Min (this IEnumerable<double> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- long minimum = long.MaxValue;
- int counter = 0;
- foreach (long element in source) {
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ Check.Source (source);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return Iterate (source, double.MaxValue, (a, b) => Math.Min (a, b));
}
-
- public static long? Min (this IEnumerable<long?> source)
+ public static float Min (this IEnumerable<float> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- long? minimum = long.MaxValue;
- foreach (long? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
- }
+ Check.Source (source);
+ return Iterate (source, float.MaxValue, (a, b) => Math.Min (a, b));
+ }
- public static double Min (this IEnumerable<double> source)
+ public static decimal Min (this IEnumerable<decimal> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- double minimum = double.MaxValue;
- int counter = 0;
- foreach (double element in source) {
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ return Iterate (source, decimal.MaxValue, (a, b) => Math.Min (a, b));
+ }
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ public static int? Min (this IEnumerable<int?> source)
+ {
+ Check.Source (source);
+
+ return IterateNullable (source, (a, b) => Math.Min (a, b));
}
+ public static long? Min (this IEnumerable<long?> source)
+ {
+ Check.Source (source);
+
+ return IterateNullable (source, (a, b) => Math.Min (a, b));
+ }
public static double? Min (this IEnumerable<double?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- double? minimum = double.MaxValue;
- foreach (double? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
- }
+ Check.Source (source);
+ return IterateNullable (source, (a, b) => Math.Min (a, b));
+ }
- public static decimal Min (this IEnumerable<decimal> source)
+ public static float? Min (this IEnumerable<float?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- decimal minimum = decimal.MaxValue;
- int counter = 0;
- foreach (decimal element in source) {
- if (element < minimum)
- minimum = element;
- counter++;
- }
-
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return IterateNullable (source, (a, b) => Math.Min (a, b));
}
-
public static decimal? Min (this IEnumerable<decimal?> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool onlyNull = true;
- decimal? minimum = decimal.MaxValue;
- foreach (decimal? element in source) {
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
- }
+ Check.Source (source);
+ return IterateNullable (source, (a, b) => Math.Min (a, b));
+ }
public static TSource Min<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
bool notAssigned = true;
TSource minimum = default (TSource);
return minimum;
}
-
- public static int Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, int> selector)
+ public static int Min<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- int minimum = int.MaxValue;
- int counter = 0;
- foreach (TSource item in source) {
- int element = selector (item);
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return Iterate (source, int.MaxValue, (a, b) => Math.Min (selector (a), b));
}
-
- public static int? Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, int?> selector)
+ public static long Min<TSource> (this IEnumerable<TSource> source, Func<TSource, long> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- int? minimum = int.MaxValue;
- foreach (TSource item in source) {
- int? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
+ return Iterate (source, long.MaxValue, (a, b) => Math.Min (selector (a), b));
}
-
- public static long Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, long> selector)
+ public static double Min<TSource> (this IEnumerable<TSource> source, Func<TSource, double> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- long minimum = long.MaxValue;
- int counter = 0;
- foreach (TSource item in source) {
- long element = selector (item);
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return Iterate (source, double.MaxValue, (a, b) => Math.Min (selector (a), b));
}
-
- public static long? Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, long?> selector)
+ public static float Min<TSource> (this IEnumerable<TSource> source, Func<TSource, float> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- long? minimum = long.MaxValue;
- foreach (TSource item in source) {
- long? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
+ return Iterate (source, float.MaxValue, (a, b) => Math.Min (selector (a), b));
}
-
- public static double Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, double> selector)
+ public static decimal Min<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- double minimum = double.MaxValue;
- int counter = 0;
- foreach (TSource item in source) {
- double element = selector (item);
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return Iterate (source, decimal.MaxValue, (a, b) => Math.Min (selector (a), b));
}
-
- public static double? Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, double?> selector)
+ public static int? Min<TSource> (this IEnumerable<TSource> source, Func<TSource, int?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- double? minimum = double.MaxValue;
- foreach (TSource item in source) {
- double? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
+ return IterateNullable (source, selector, (a, b) => a < b);
}
-
- public static decimal Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, decimal> selector)
+ public static long? Min<TSource> (this IEnumerable<TSource> source, Func<TSource, long?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- decimal minimum = decimal.MaxValue;
- int counter = 0;
- foreach (TSource item in source) {
- decimal element = selector (item);
- if (element < minimum)
- minimum = element;
- counter++;
- }
+ Check.SourceAndSelector (source, selector);
- if (counter == 0)
- throw new InvalidOperationException ();
- else
- return minimum;
+ return IterateNullable (source, selector, (a, b) => a < b);
}
+ public static float? Min<TSource> (this IEnumerable<TSource> source, Func<TSource, float?> selector)
+ {
+ Check.SourceAndSelector (source, selector);
+
+ return IterateNullable (source, selector, (a, b) => a < b);
+ }
- public static decimal? Min<TSource> (this IEnumerable<TSource> source,
- Func<TSource, decimal?> selector)
+ public static double? Min<TSource> (this IEnumerable<TSource> source, Func<TSource, double?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- bool onlyNull = true;
- decimal? minimum = decimal.MaxValue;
- foreach (TSource item in source) {
- decimal? element = selector (item);
- if (element.HasValue) {
- onlyNull = false;
- if (element < minimum)
- minimum = element;
- }
- }
- return (onlyNull ? null : minimum);
+ return IterateNullable (source, selector, (a, b) => a < b);
}
+ public static decimal? Min<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal?> selector)
+ {
+ Check.SourceAndSelector (source, selector);
+
+ return IterateNullable (source, selector, (a, b) => a < b);
+ }
- public static TResult Min<TSource, TResult> (this IEnumerable<TSource> source,
- Func<TSource, TResult> selector)
+ public static TResult Min<TSource, TResult> (this IEnumerable<TSource> source, Func<TSource, TResult> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
bool notAssigned = true;
TResult minimum = default (TResult);
public static IEnumerable<TResult> OfType<TResult> (this IEnumerable source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+ return CreateOfTypeIterator<TResult> (source);
+ }
+
+ static IEnumerable<TResult> CreateOfTypeIterator<TResult> (IEnumerable source)
+ {
foreach (object element in source)
if (element is TResult)
yield return (TResult) element;
return OrderBy<TSource, TKey> (source, keySelector, null);
}
-
public static IOrderedEnumerable<TSource> OrderBy<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey> comparer)
{
- if (source == null || keySelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeySelector (source, keySelector);
- return new InternalOrderedSequence<TSource, TKey> (
- source, keySelector, comparer, false);
+ return new OrderedSequence<TSource, TKey> (source, keySelector, comparer, SortDirection.Ascending);
}
#endregion
return OrderByDescending<TSource, TKey> (source, keySelector, null);
}
-
public static IOrderedEnumerable<TSource> OrderByDescending<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
{
- if (source == null || keySelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeySelector (source, keySelector);
- return new InternalOrderedSequence<TSource, TKey> (
- source, keySelector, comparer, true);
+ return new OrderedSequence<TSource, TKey> (source, keySelector, comparer, SortDirection.Descending);
}
#endregion
public static IEnumerable<int> Range (int start, int count)
{
- if (count < 0 || (start + count - 1) > int.MaxValue)
+ if (count < 0)
+ throw new ArgumentOutOfRangeException ("count");
+
+ long upto = ((long) start + count) - 1;
+
+ if (upto > int.MaxValue)
throw new ArgumentOutOfRangeException ();
- for (int i = start; i < (start + count - 1); i++)
+ return CreateRangeIterator (start, (int) upto);
+ }
+
+ static IEnumerable<int> CreateRangeIterator (int start, int upto)
+ {
+ for (int i = start; i <= upto; i++)
yield return i;
}
if (count < 0)
throw new ArgumentOutOfRangeException ();
+ return CreateRepeatIterator (element, count);
+ }
+
+ static IEnumerable<TResult> CreateRepeatIterator<TResult> (TResult element, int count)
+ {
for (int i = 0; i < count; i++)
yield return element;
}
#endregion
-
#region Reverse
public static IEnumerable<TSource> Reverse<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+
+ var list = source as IList<TSource>;
+ if (list == null)
+ list = new List<TSource> (source);
+
+ return CreateReverseIterator (list);
+ }
- List<TSource> list = new List<TSource> (source);
- list.Reverse ();
- return list;
+ static IEnumerable<TSource> CreateReverseIterator<TSource> (IList<TSource> source)
+ {
+ for (int i = source.Count; i > 0; --i)
+ yield return source [i - 1];
}
#endregion
#region Select
- public static IEnumerable<TResult> Select<TSource, TResult> (this IEnumerable<TSource> source,
- Func<TSource, TResult> selector)
+ public static IEnumerable<TResult> Select<TSource, TResult> (this IEnumerable<TSource> source, Func<TSource, TResult> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- foreach (TSource element in source)
- yield return selector (element);
+ return CreateSelectIterator (source, selector);
}
+ static IEnumerable<TResult> CreateSelectIterator<TSource, TResult> (IEnumerable<TSource> source, Func<TSource, TResult> selector)
+ {
+ foreach (var element in source)
+ yield return selector (element);
+ }
- public static IEnumerable<TResult> Select<TSource, TResult> (this IEnumerable<TSource> source,
- Func<TSource, int, TResult> selector)
+ public static IEnumerable<TResult> Select<TSource, TResult> (this IEnumerable<TSource> source, Func<TSource, int, TResult> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
+ return CreateSelectIterator (source, selector);
+ }
+
+ static IEnumerable<TResult> CreateSelectIterator<TSource, TResult> (IEnumerable<TSource> source, Func<TSource, int, TResult> selector)
+ {
int counter = 0;
foreach (TSource element in source) {
yield return selector (element, counter);
#region SelectMany
- public static IEnumerable<TResult> SelectMany<TSource, TResult> (this IEnumerable<TSource> source,
- Func<TSource, IEnumerable<TResult>> selector)
+ public static IEnumerable<TResult> SelectMany<TSource, TResult> (this IEnumerable<TSource> source, Func<TSource, IEnumerable<TResult>> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
+ return CreateSelectManyIterator (source, selector);
+ }
+
+ static IEnumerable<TResult> CreateSelectManyIterator<TSource, TResult> (IEnumerable<TSource> source, Func<TSource, IEnumerable<TResult>> selector)
+ {
foreach (TSource element in source)
foreach (TResult item in selector (element))
yield return item;
}
-
- public static IEnumerable<TResult> SelectMany<TSource, TResult> (this IEnumerable<TSource> source,
- Func<TSource, int, IEnumerable<TResult>> selector)
+ public static IEnumerable<TResult> SelectMany<TSource, TResult> (this IEnumerable<TSource> source, Func<TSource, int, IEnumerable<TResult>> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
+ return CreateSelectManyIterator (source, selector);
+ }
+
+ static IEnumerable<TResult> CreateSelectManyIterator<TSource, TResult> (IEnumerable<TSource> source, Func<TSource, int, IEnumerable<TResult>> selector)
+ {
int counter = 0;
foreach (TSource element in source) {
- foreach (TResult item in selector (element, counter++))
+ foreach (TResult item in selector (element, counter))
yield return item;
counter++;
}
public static IEnumerable<TResult> SelectMany<TSource, TCollection, TResult> (this IEnumerable<TSource> source,
Func<TSource, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> selector)
{
- if (source == null || collectionSelector == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndCollectionSelectors (source, collectionSelector, selector);
+
+ return CreateSelectManyIterator (source, collectionSelector, selector);
+ }
+ static IEnumerable<TResult> CreateSelectManyIterator<TSource, TCollection, TResult> (IEnumerable<TSource> source,
+ Func<TSource, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> selector)
+ {
foreach (TSource element in source)
foreach (TCollection collection in collectionSelector (element))
yield return selector (element, collection);
}
public static IEnumerable<TResult> SelectMany<TSource, TCollection, TResult> (this IEnumerable<TSource> source,
- Func<TSource, int, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> selector)
+ Func<TSource, int, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> selector)
{
- if (source == null || collectionSelector == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndCollectionSelectors (source, collectionSelector, selector);
+
+ return CreateSelectManyIterator (source, collectionSelector, selector);
+ }
+ static IEnumerable<TResult> CreateSelectManyIterator<TSource, TCollection, TResult> (IEnumerable<TSource> source,
+ Func<TSource, int, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> selector)
+ {
int counter = 0;
foreach (TSource element in source)
foreach (TCollection collection in collectionSelector (element, counter++))
#region Single
- public static TSource Single<TSource> (this IEnumerable<TSource> source)
+ static TSource Single<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate, Fallback fallback)
{
- if (source == null)
- throw new ArgumentNullException ();
+ var found = false;
+ var item = default (TSource);
- bool otherElement = false;
- TSource singleElement = default (TSource);
- foreach (TSource element in source) {
- if (otherElement) throw new InvalidOperationException ();
- if (!otherElement) otherElement = true;
- singleElement = element;
+ foreach (var element in source) {
+ if (!predicate (element))
+ continue;
+
+ if (found)
+ throw new InvalidOperationException ();
+
+ found = true;
+ item = element;
}
- if (otherElement)
- return singleElement;
- else
+ if (!found && fallback == Fallback.Throw)
throw new InvalidOperationException ();
- }
+ return item;
+ }
- public static TSource Single<TSource> (this IEnumerable<TSource> source,
- Func<TSource, bool> predicate)
+ public static TSource Single<TSource> (this IEnumerable<TSource> source)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- bool otherElement = false;
- TSource singleElement = default (TSource);
- foreach (TSource element in source) {
- if (predicate (element)) {
- if (otherElement) throw new InvalidOperationException ();
- if (!otherElement) otherElement = true;
- singleElement = element;
- }
- }
+ return source.Single (PredicateOf<TSource>.Always, Fallback.Throw);
+ }
- if (otherElement)
- return singleElement;
- else
- throw new InvalidOperationException ();
+ public static TSource Single<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ {
+ Check.SourceAndPredicate (source, predicate);
+
+ return source.Single (predicate, Fallback.Throw);
}
#endregion
public static TSource SingleOrDefault<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- bool otherElement = false;
- TSource singleElement = default (TSource);
- foreach (TSource element in source) {
- if (otherElement) throw new InvalidOperationException ();
- if (!otherElement) otherElement = true;
- singleElement = element;
- }
+ Check.Source (source);
- return singleElement;
+ return source.Single (PredicateOf<TSource>.Always, Fallback.Default);
}
-
- public static TSource SingleOrDefault<TSource> (this IEnumerable<TSource> source,
- Func<TSource, bool> predicate)
+ public static TSource SingleOrDefault<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
-
- bool otherElement = false;
- TSource singleElement = default (TSource);
- foreach (TSource element in source) {
- if (predicate (element)) {
- if (otherElement) throw new InvalidOperationException ();
- if (!otherElement) otherElement = true;
- singleElement = element;
- }
- }
+ Check.SourceAndPredicate (source, predicate);
- return singleElement;
+ return source.Single (predicate, Fallback.Default);
}
#endregion
#region Skip
+
public static IEnumerable<TSource> Skip<TSource> (this IEnumerable<TSource> source, int count)
{
- if (source == null)
- throw new NotSupportedException ();
+ Check.Source (source);
+ return CreateSkipIterator (source, count);
+ }
+
+ static IEnumerable<TSource> CreateSkipIterator<TSource> (IEnumerable<TSource> source, int count)
+ {
int i = 0;
- foreach (TSource e in source) {
- if (++i < count)
+ foreach (var element in source) {
+ if (i++ < count)
continue;
- yield return e;
+
+ yield return element;
}
}
+
#endregion
#region SkipWhile
-
- public static IEnumerable<TSource> SkipWhile<TSource> (
- this IEnumerable<TSource> source,
- Func<TSource, bool> predicate)
+ public static IEnumerable<TSource> SkipWhile<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
+
+ return CreateSkipWhileIterator (source, predicate);
+ }
+ static IEnumerable<TSource> CreateSkipWhileIterator<TSource> (IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ {
bool yield = false;
foreach (TSource element in source) {
}
}
-
- public static IEnumerable<TSource> SkipWhile<TSource> (this IEnumerable<TSource> source,
- Func<TSource, int, bool> predicate)
+ public static IEnumerable<TSource> SkipWhile<TSource> (this IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
+
+ return CreateSkipWhileIterator (source, predicate);
+ }
+ static IEnumerable<TSource> CreateSkipWhileIterator<TSource> (IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
+ {
int counter = 0;
bool yield = false;
public static int Sum (this IEnumerable<int> source)
{
- if (source == null)
- throw new ArgumentNullException ("source");
-
- int sum = 0;
- foreach (int element in source)
- sum += element;
+ Check.Source (source);
- return sum;
+ return Sum<int, int> (source, (a, b) => checked (a + b));
}
-
- public static int Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
+ public static int? Sum (this IEnumerable<int?> source)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- int sum = 0;
- foreach (TSource element in source)
- sum += selector (element);
+ Check.Source (source);
- return sum;
+ return source.SumNullable<int?, int?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
-
- public static int? Sum (this IEnumerable<int?> source)
+ public static int Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- int? sum = 0;
- foreach (int? element in source)
- if (element.HasValue)
- sum += element.Value;
+ Check.SourceAndSelector (source, selector);
- return sum;
+ return Sum<TSource, int> (source, (a, b) => checked (a + selector (b)));
}
-
public static int? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, int?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- int? sum = 0;
- foreach (TSource element in source) {
- int? item = selector (element);
- if (item.HasValue)
- sum += item.Value;
- }
+ Check.SourceAndSelector (source, selector);
- return sum;
+ return source.SumNullable<TSource, int?> (0, (a, b) => {
+ var value = selector (b);
+ return value.HasValue ? checked (a + value.Value) : a;
+ });
}
-
public static long Sum (this IEnumerable<long> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- long sum = 0;
- foreach (long element in source)
- sum += element;
-
- return sum;
+ return Sum<long, long> (source, (a, b) => checked (a + b));
}
-
- public static long Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, long> selector)
+ public static long? Sum (this IEnumerable<long?> source)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- long sum = 0;
- foreach (TSource element in source)
- sum += selector (element);
-
- return sum;
+ return source.SumNullable<long?, long?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
-
- public static long? Sum (this IEnumerable<long?> source)
+ public static long Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, long> selector)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- long? sum = 0;
- foreach (long? element in source)
- if (element.HasValue)
- sum += element.Value;
-
- return sum;
+ return Sum<TSource, long> (source, (a, b) => checked (a + selector (b)));
}
-
public static long? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, long?> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- long? sum = 0;
- foreach (TSource element in source) {
- long? item = selector (element);
- if (item.HasValue)
- sum += item.Value;
- }
-
- return sum;
+ return source.SumNullable<TSource, long?> (0, (a, b) => {
+ var value = selector (b);
+ return value.HasValue ? checked (a + value.Value) : a;
+ });
}
-
public static double Sum (this IEnumerable<double> source)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- double sum = 0;
- foreach (double element in source)
- sum += element;
+ Check.Source (source);
- return sum;
+ return Sum<double, double> (source, (a, b) => checked (a + b));
}
+ public static double? Sum (this IEnumerable<double?> source)
+ {
+ Check.Source (source);
+
+ return source.SumNullable<double?, double?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
+ }
public static double Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, double> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- double sum = 0;
- foreach (TSource element in source)
- sum += selector (element);
+ Check.SourceAndSelector (source, selector);
- return sum;
+ return Sum<TSource, double> (source, (a, b) => checked (a + selector (b)));
}
-
- public static double? Sum (this IEnumerable<double?> source)
+ public static double? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, double?> selector)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.SourceAndSelector (source, selector);
- double? sum = 0;
- foreach (double? element in source)
- if (element.HasValue)
- sum += element.Value;
-
- return sum;
+ return source.SumNullable<TSource, double?> (0, (a, b) => {
+ var value = selector (b);
+ return value.HasValue ? checked (a + value.Value) : a;
+ });
}
+ public static float Sum (this IEnumerable<float> source)
+ {
+ Check.Source (source);
- public static double? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, double?> selector)
+ return Sum<float, float> (source, (a, b) => checked (a + b));
+ }
+
+ public static float? Sum (this IEnumerable<float?> source)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- double? sum = 0;
- foreach (TSource element in source) {
- double? item = selector (element);
- if (item.HasValue)
- sum += item.Value;
- }
+ return source.SumNullable<float?, float?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
+ }
- return sum;
+ public static float Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, float> selector)
+ {
+ Check.SourceAndSelector (source, selector);
+
+ return Sum<TSource, float> (source, (a, b) => checked (a + selector (b)));
}
+ public static float? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, float?> selector)
+ {
+ Check.SourceAndSelector (source, selector);
+
+ return source.SumNullable<TSource, float?> (0, (a, b) => {
+ var value = selector (b);
+ return value.HasValue ? checked (a + value.Value) : a;
+ });
+ }
public static decimal Sum (this IEnumerable<decimal> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
- decimal sum = 0;
- foreach (decimal element in source)
- sum += element;
-
- return sum;
+ return Sum<decimal, decimal> (source, (a, b) => checked (a + b));
}
+ public static decimal? Sum (this IEnumerable<decimal?> source)
+ {
+ Check.Source (source);
+
+ return source.SumNullable<decimal?, decimal?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
+ }
public static decimal Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
-
- decimal sum = 0;
- foreach (TSource element in source)
- sum += selector (element);
+ Check.SourceAndSelector (source, selector);
- return sum;
+ return Sum<TSource, decimal> (source, (a, b) => checked (a + selector (b)));
}
-
- public static decimal? Sum (this IEnumerable<decimal?> source)
+ public static decimal? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal?> selector)
{
- if (source == null)
- throw new ArgumentNullException ();
-
- decimal? sum = 0;
- foreach (decimal? element in source)
- if (element.HasValue)
- sum += element.Value;
+ Check.SourceAndSelector (source, selector);
- return sum;
+ return source.SumNullable<TSource, decimal?> (0, (a, b) => {
+ var value = selector (b);
+ return value.HasValue ? checked (a + value.Value) : a;
+ });
}
-
- public static decimal? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal?> selector)
+ static TR Sum<TA, TR> (this IEnumerable<TA> source, Func<TR, TA, TR> selector)
{
- if (source == null || selector == null)
- throw new ArgumentNullException ();
+ TR total = default (TR);
+ long counter = 0;
+ foreach (var element in source) {
+ total = selector (total, element);
+ ++counter;
+ }
- decimal? sum = 0;
- foreach (TSource element in source) {
- decimal? item = selector (element);
- if (item.HasValue)
- sum += item.Value;
+ return total;
+ }
+
+ static TR SumNullable<TA, TR> (this IEnumerable<TA> source, TR zero, Func<TR, TA, TR> selector)
+ {
+ TR total = zero;
+ foreach (var element in source) {
+ total = selector (total, element);
}
- return sum;
+ return total;
}
#endregion
+
#region Take
public static IEnumerable<TSource> Take<TSource> (this IEnumerable<TSource> source, int count)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+ return CreateTakeIterator (source, count);
+ }
+
+ static IEnumerable<TSource> CreateTakeIterator<TSource> (IEnumerable<TSource> source, int count)
+ {
if (count <= 0)
yield break;
- else {
- int counter = 0;
- foreach (TSource element in source) {
- yield return element;
- counter++;
- if (counter == count)
- yield break;
- }
+
+ int counter = 0;
+ foreach (TSource element in source) {
+ yield return element;
+
+ if (++counter == count)
+ yield break;
}
}
public static IEnumerable<TSource> TakeWhile<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
- foreach (TSource element in source) {
- if (predicate (element))
- yield return element;
- else
+ return CreateTakeWhileIterator (source, predicate);
+ }
+
+ static IEnumerable<TSource> CreateTakeWhileIterator<TSource> (IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ {
+ foreach (var element in source) {
+ if (!predicate (element))
yield break;
+
+ yield return element;
}
}
public static IEnumerable<TSource> TakeWhile<TSource> (this IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
+
+ return CreateTakeWhileIterator (source, predicate);
+ }
+ static IEnumerable<TSource> CreateTakeWhileIterator<TSource> (IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
+ {
int counter = 0;
- foreach (TSource element in source) {
- if (predicate (element, counter))
- yield return element;
- else
+ foreach (var element in source) {
+ if (!predicate (element, counter))
yield break;
+
+ yield return element;
counter++;
}
}
return ThenBy<TSource, TKey> (source, keySelector, null);
}
-
public static IOrderedEnumerable<TSource> ThenBy<TSource, TKey> (this IOrderedEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
{
- if (source == null || keySelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeySelector (source, keySelector);
return source.CreateOrderedEnumerable (keySelector, comparer, false);
}
return ThenByDescending<TSource, TKey> (source, keySelector, null);
}
-
public static IOrderedEnumerable<TSource> ThenByDescending<TSource, TKey> (this IOrderedEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
{
- if (source == null || keySelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeySelector (source, keySelector);
return source.CreateOrderedEnumerable (keySelector, comparer, true);
}
#endregion
#region ToArray
+
public static TSource [] ToArray<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ();
+ Check.Source (source);
+
+ var collection = source as ICollection<TSource>;
+ if (collection != null) {
+ var array = new TSource [collection.Count];
+ collection.CopyTo (array, 0);
+ return array;
+ }
- List<TSource> list = new List<TSource> (source);
- return list.ToArray ();
+ return new List<TSource> (source).ToArray ();
}
#endregion
#region ToDictionary
- public static Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement> (this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector)
+ public static Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector)
{
return ToDictionary<TSource, TKey, TElement> (source, keySelector, elementSelector, null);
}
-
- public static Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement> (this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
+ public static Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
{
- if (source == null)
- throw new ArgumentNullException ("source");
- if (keySelector == null)
- throw new ArgumentNullException ("keySelector");
- if (elementSelector == null)
- throw new ArgumentNullException ("elementSelector");
-
- Dictionary<TKey, TElement> dict = new Dictionary<TKey, TElement> (comparer);
- foreach (TSource e in source) {
+ Check.SourceAndKeyElementSelectors (source, keySelector, elementSelector);
+
+ if (comparer == null)
+ comparer = EqualityComparer<TKey>.Default;
+
+ var dict = new Dictionary<TKey, TElement> (comparer);
+ foreach (var e in source)
dict.Add (keySelector (e), elementSelector (e));
- }
return dict;
}
+
+ public static Dictionary<TKey, TSource> ToDictionary<TSource, TKey> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector)
+ {
+ return ToDictionary (source, keySelector, null);
+ }
+
+ public static Dictionary<TKey, TSource> ToDictionary<TSource, TKey> (this IEnumerable<TSource> source,
+ Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+ {
+ return ToDictionary<TSource, TKey, TSource> (source, keySelector, Function<TSource>.Identity, comparer);
+ }
+
#endregion
#region ToList
public static List<TSource> ToList<TSource> (this IEnumerable<TSource> source)
{
- if (source == null)
- throw new ArgumentNullException ("source");
+ Check.Source (source);
return new List<TSource> (source);
}
#region ToLookup
- public static Lookup<TKey, TSource> ToLookup<TSource, TKey> (this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
+ public static ILookup<TKey, TSource> ToLookup<TSource, TKey> (this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
{
- return ToLookup<TSource, TKey> (source, keySelector, null);
+ return ToLookup<TSource, TKey, TSource> (source, keySelector, Function<TSource>.Identity, null);
}
-
- public static Lookup<TKey, TSource> ToLookup<TSource, TKey> (this IEnumerable<TSource> source,
+ public static ILookup<TKey, TSource> ToLookup<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
{
- if (source == null || keySelector == null)
- throw new ArgumentNullException ();
-
- Dictionary<TKey, List<TSource>> dictionary = new Dictionary<TKey, List<TSource>> (comparer ?? EqualityComparer<TKey>.Default);
- foreach (TSource element in source) {
- TKey key = keySelector (element);
- if (key == null)
- throw new ArgumentNullException ();
- if (!dictionary.ContainsKey (key))
- dictionary.Add (key, new List<TSource> ());
- dictionary [key].Add (element);
- }
- return new Lookup<TKey, TSource> (dictionary);
+ return ToLookup<TSource, TKey, TSource> (source, keySelector, element => element, comparer);
}
-
- public static Lookup<TKey, TElement> ToLookup<TSource, TKey, TElement> (this IEnumerable<TSource> source,
+ public static ILookup<TKey, TElement> ToLookup<TSource, TKey, TElement> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector)
{
return ToLookup<TSource, TKey, TElement> (source, keySelector, elementSelector, null);
}
-
- public static Lookup<TKey, TElement> ToLookup<TSource, TKey, TElement> (this IEnumerable<TSource> source,
+ public static ILookup<TKey, TElement> ToLookup<TSource, TKey, TElement> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
{
- if (source == null || keySelector == null || elementSelector == null)
- throw new ArgumentNullException ();
+ Check.SourceAndKeyElementSelectors (source, keySelector, elementSelector);
- Dictionary<TKey, List<TElement>> dictionary = new Dictionary<TKey, List<TElement>> (comparer ?? EqualityComparer<TKey>.Default);
- foreach (TSource element in source) {
- TKey key = keySelector (element);
+ var dictionary = new Dictionary<TKey, List<TElement>> (comparer ?? EqualityComparer<TKey>.Default);
+ foreach (var element in source) {
+ var key = keySelector (element);
if (key == null)
- throw new ArgumentNullException ();
- if (!dictionary.ContainsKey (key))
- dictionary.Add (key, new List<TElement> ());
- dictionary [key].Add (elementSelector (element));
+ throw new ArgumentNullException ("key");
+
+ List<TElement> list;
+ if (!dictionary.TryGetValue (key, out list)) {
+ list = new List<TElement> ();
+ dictionary.Add (key, list);
+ }
+
+ list.Add (elementSelector (element));
}
+
return new Lookup<TKey, TElement> (dictionary);
}
#endregion
- #region ToSequence
+ #region SequenceEqual
+
+ public static bool SequenceEqual<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second)
+ {
+ return first.SequenceEqual (second, null);
+ }
- public static IEnumerable<T> ToSequence<T> (this IEnumerable<T> source)
+ public static bool SequenceEqual<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
{
- return (IEnumerable<T>) source;
+ Check.FirstAndSecond (first, second);
+
+ if (comparer == null)
+ comparer = EqualityComparer<TSource>.Default;
+
+ using (IEnumerator<TSource> first_enumerator = first.GetEnumerator (),
+ second_enumerator = second.GetEnumerator ()) {
+
+ while (first_enumerator.MoveNext ()) {
+ if (!second_enumerator.MoveNext ())
+ return false;
+
+ if (!comparer.Equals (first_enumerator.Current, second_enumerator.Current))
+ return false;
+ }
+
+ return !second_enumerator.MoveNext ();
+ }
}
#endregion
#region Union
-
public static IEnumerable<TSource> Union<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second)
{
- if (first == null || second == null)
- throw new ArgumentNullException ();
+ Check.FirstAndSecond (first, second);
- List<TSource> items = new List<TSource> ();
- foreach (TSource element in first) {
- if (IndexOf (items, element) == -1) {
+ return first.Union (second, null);
+ }
+
+ public static IEnumerable<TSource> Union<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
+ {
+ Check.FirstAndSecond (first, second);
+
+ if (comparer == null)
+ comparer = EqualityComparer<TSource>.Default;
+
+ return CreateUnionIterator (first, second, comparer);
+ }
+
+ static IEnumerable<TSource> CreateUnionIterator<TSource> (IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
+ {
+ var items = new HashSet<TSource> (comparer);
+ foreach (var element in first) {
+ if (! items.Contains (element)) {
items.Add (element);
yield return element;
}
}
- foreach (TSource element in second) {
- if (IndexOf (items, element) == -1) {
+
+ foreach (var element in second) {
+ if (! items.Contains (element, comparer)) {
items.Add (element);
yield return element;
}
#region Where
- public static IEnumerable<TSource> Where<TSource> (this IEnumerable<TSource> source,
- Func<TSource, bool> predicate)
+ public static IEnumerable<TSource> Where<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
+ return CreateWhereIterator (source, predicate);
+ }
+
+ static IEnumerable<TSource> CreateWhereIterator<TSource> (IEnumerable<TSource> source, Func<TSource, bool> predicate)
+ {
foreach (TSource element in source)
if (predicate (element))
yield return element;
}
-
- public static IEnumerable<TSource> Where<TSource> (this IEnumerable<TSource> source,
- Func<TSource, int, bool> predicate)
+ public static IEnumerable<TSource> Where<TSource> (this IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
{
- if (source == null || predicate == null)
- throw new ArgumentNullException ();
+ Check.SourceAndPredicate (source, predicate);
+ return CreateWhereIterator (source, predicate);
+ }
+
+ static IEnumerable<TSource> CreateWhereIterator<TSource> (this IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
+ {
int counter = 0;
foreach (TSource element in source) {
if (predicate (element, counter))
#endregion
- // These methods are not included in the
- // .NET Standard Query Operators Specification,
- // but they provide additional useful commands
-
- #region Compare
-
- private static bool Equals<T> (T first, T second)
- {
- // Mostly, values in Enumerable<T>
- // sequences need to be compared using
- // Equals and GetHashCode
-
- if (first == null || second == null)
- return (first == null && second == null);
- else
- return ((first.Equals (second) ||
- first.GetHashCode () == second.GetHashCode ()));
- }
-
- #endregion
-
- #region IndexOf
-
- static int IndexOf<T> (this IEnumerable<T> source, T item, IEqualityComparer<T> comparer)
- {
- if (comparer == null)
- comparer = EqualityComparer<T>.Default;
-
- int counter = 0;
- foreach (T element in source) {
- if (comparer.Equals (element, item))
- return counter;
- counter++;
- }
- // The item was not found
- return -1;
- }
-
- static int IndexOf<T> (this IEnumerable<T> source, T item)
- {
- return IndexOf<T> (source, item, null);
+ class ReadOnlyCollectionOf<T> {
+ public static readonly ReadOnlyCollection<T> Empty = new ReadOnlyCollection<T> (new T [0]);
}
- #endregion
- #region ToReadOnlyCollection
- internal static ReadOnlyCollection<TSource> ToReadOnlyCollection<TSource> (IEnumerable<TSource> source)
+ internal static ReadOnlyCollection<TSource> ToReadOnlyCollection<TSource> (this IEnumerable<TSource> source)
{
if (source == null)
- return new ReadOnlyCollection<TSource> (new List<TSource> ());
+ return ReadOnlyCollectionOf<TSource>.Empty;
- if (typeof (ReadOnlyCollection<TSource>).IsInstanceOfType (source))
- return source as ReadOnlyCollection<TSource>;
+ var ro = source as ReadOnlyCollection<TSource>;
+ if (ro != null)
+ return ro;
- return new ReadOnlyCollection<TSource> (ToArray<TSource> (source));
+ return new ReadOnlyCollection<TSource> (source.ToArray<TSource> ());
}
- #endregion
}
}
projects / mono.git / blobdiff