// Transferred from Mono to Loyc by David Piepgrass.
// 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
// without limitation the rights to use, copy, modify, merge, publish,
// 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
//
// Authors:
// Marek Safar (marek.safar@gmail.com)
// Antonello Provenzano <antonello@deveel.com>
// Alejandro Serrano "Serras" (trupill@yahoo.es)
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
namespace Compatibility.Linq
{
public delegate TResult Func<TResult>();
public delegate TResult Func<TArg0, TResult>(TArg0 arg0);
public delegate TResult Func<TArg0, TArg1, TResult>(TArg0 arg0, TArg1 arg1);
public delegate TResult Func<TArg0, TArg1, TArg2, TResult>(TArg0 arg0, TArg1 arg1, TArg2 arg2);
public delegate TResult Func<TArg0, TArg1, TArg2, TArg3, TResult>(TArg0 arg0, TArg1 arg1, TArg2 arg2, TArg3 arg3);
public static class Enumerable
{
#region Aggregate
public static TSource Aggregate<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, TSource, TSource> func)
{
if (source == null || func == null)
throw new ArgumentNullException();
int counter = 0;
TSource folded = default(TSource);
foreach (TSource element in source)
{
if (counter == 0)
folded = element;
else
folded = func(folded, element);
}
if (counter == 0)
throw new InvalidOperationException();
else
return folded;
}
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();
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");
if (resultSelector == null)
throw new ArgumentNullException("resultSelector");
TAccumulate result = seed;
foreach (TSource 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();
foreach (TSource 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();
foreach (TSource element in source)
return true;
return false;
}
public static bool Any<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
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;
}
public static double? Average(/*this*/ IEnumerable<int?> source)
{
if (source == null)
throw new ArgumentNullException();
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 double Average(/*this*/ IEnumerable<long> source)
{
if (source == null)
throw new ArgumentNullException();
long sum = 0;
long counter = 0;
foreach (long element in source)
{
sum += element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return (double)sum / (double)counter;
}
public static double? Average(/*this*/ IEnumerable<long?> source)
{
if (source == null)
throw new ArgumentNullException();
bool onlyNull = true;
long sum = 0;
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();
double sum = 0;
double counter = 0;
foreach (double element in source)
{
sum += element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return sum / counter;
}
public static double? Average(/*this*/ IEnumerable<double?> 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));
}
public static decimal Average(/*this*/ IEnumerable<decimal> source)
{
if (source == null)
throw new ArgumentNullException();
decimal sum = 0;
decimal counter = 0;
foreach (decimal element in source)
{
sum += element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return sum / counter;
}
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));
}
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return (double)sum / (double)counter;
}
public static double? Average<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, int?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return (double)sum / (double)counter;
}
public static double? Average<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, long?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return sum / counter;
}
public static double? Average<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, double?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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));
}
public static decimal Average<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, decimal> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
decimal sum = 0;
decimal counter = 0;
foreach (TSource item in source)
{
sum += selector(item);
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return sum / counter;
}
public static decimal? Average<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, decimal?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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));
}
#endregion
#region Cast
public static IEnumerable<TSource> Cast<TSource>(/*this*/ IEnumerable source)
{
if (source == null)
throw new ArgumentNullException();
foreach (object element in source)
yield return (TSource)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();
foreach (TSource element in first)
yield return element;
foreach (TSource element in second)
yield return element;
}
#endregion
#region Contains
public static bool Contains<TSource>(/*this*/ IEnumerable<TSource> source, TSource value)
{
if (source is ICollection<TSource>)
{
ICollection<TSource> collection = (ICollection<TSource>)source;
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");
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
foreach (TSource e in source)
{
if (comparer.Equals(e, value))
return true;
}
return false;
}
#endregion
#region Count
public static int Count<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
if (source is ICollection<TSource>)
return ((ICollection<TSource>)source).Count;
else
{
int counter = 0;
foreach (TSource element in source)
counter++;
return counter;
}
}
public static int Count<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, bool> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
int counter = 0;
foreach (TSource element in source)
if (selector(element))
counter++;
return counter;
}
#endregion
#region DefaultIfEmpty
public static IEnumerable<TSource> DefaultIfEmpty<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
bool noYield = true;
foreach (TSource item in source)
{
noYield = false;
yield return item;
}
if (noYield)
yield return default(TSource);
}
public static IEnumerable<TSource> DefaultIfEmpty<TSource>(/*this*/ IEnumerable<TSource> source, TSource defaultValue)
{
if (source == null)
throw new ArgumentNullException();
bool noYield = true;
foreach (TSource item in source)
{
noYield = false;
yield return item;
}
if (noYield)
yield return defaultValue;
}
#endregion
#region Distinct
public static IEnumerable<TSource> Distinct<TSource>(/*this*/ IEnumerable<TSource> source)
{
return Distinct<TSource>(source, null);
}
public static IEnumerable<TSource> Distinct<TSource>(/*this*/ IEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
{
if (source == null)
throw new ArgumentNullException();
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
List<TSource> items = new List<TSource>();
foreach (TSource element in source)
{
if (!Contains (items, element, comparer))
{
items.Add(element);
yield return element;
}
}
}
#endregion
#region ElementAt
public static TSource ElementAt<TSource>(/*this*/ IEnumerable<TSource> source, int index)
{
if (source == null)
throw new ArgumentNullException();
if (index < 0)
throw new ArgumentOutOfRangeException();
if (source is IList<TSource>)
return ((IList<TSource>)source)[index];
else
{
int counter = 0;
foreach (TSource element in source)
{
if (counter == index)
return element;
counter++;
}
throw new ArgumentOutOfRangeException();
}
}
#endregion
#region ElementAtOrDefault
public static TSource ElementAtOrDefault<TSource>(/*this*/ IEnumerable<TSource> source, int index)
{
if (source == null)
throw new ArgumentNullException();
if (index < 0)
return default(TSource);
if (source is IList<TSource>)
{
if (((IList<TSource>)source).Count >= index)
return default(TSource);
else
return ((IList<TSource>)source)[index];
}
else
{
int counter = 0;
foreach (TSource element in source)
{
if (counter == index)
return element;
counter++;
}
return default(TSource);
}
}
#endregion
#region Empty
public static IEnumerable<TResult> Empty<TResult>()
{
return new List<TResult>();
}
#endregion
#region Except
public static IEnumerable<TSource> Except<TSource>(/*this*/ IEnumerable<TSource> first, IEnumerable<TSource> second)
{
return Except(first, second, null);
}
public static IEnumerable<TSource> Except<TSource>(/*this*/ IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
{
if (first == null || second == null)
throw new ArgumentNullException();
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
List<TSource> items = new List<TSource>(Distinct(first));
foreach (TSource element in second)
{
int index = IndexOf(items, element, comparer);
if (index == -1)
items.Add(element);
else
items.RemoveAt(index);
}
foreach (TSource item in items)
yield return item;
}
#endregion
#region First
public static TSource First<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
foreach (TSource element in source)
return element;
throw new InvalidOperationException();
}
public static TSource First<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
foreach (TSource element in source)
{
if (predicate(element))
return element;
}
throw new InvalidOperationException();
}
#endregion
#region FirstOrDefault
public static T FirstOrDefault<T>(/*this*/ IEnumerable<T> source)
{
if (source == null)
throw new ArgumentNullException();
foreach (T element in source)
return element;
return default(T);
}
public static T FirstOrDefault<T>(/*this*/ IEnumerable<T> source, Func<T, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
foreach (T element in source)
{
if (predicate(element))
return element;
}
return default(T);
}
#endregion
#region GroupBy
private static List<T> ContainsGroup<K, T>(
Dictionary<K, List<T>> items, K key, IEqualityComparer<K> comparer)
{
IEqualityComparer<K> comparerInUse = (comparer ?? EqualityComparer<K>.Default);
foreach (KeyValuePair<K, List<T>> value in items)
{
if (comparerInUse.Equals(value.Key, key))
return value.Value;
}
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();
Dictionary<TKey, List<TSource>> groups = new Dictionary<TKey, List<TSource>>();
List<TSource> nullList = new List<TSource>();
int counter = 0;
int nullCounter = -1;
foreach (TSource element in source)
{
TKey key = keySelector(element);
if (key == null)
{
nullList.Add(element);
if (nullCounter == -1)
{
nullCounter = counter;
counter++;
}
}
else
{
List<TSource> group = ContainsGroup<TKey, TSource>(groups, key, comparer);
if (group == null)
{
group = new List<TSource>();
groups.Add(key, group);
counter++;
}
group.Add(element);
}
}
counter = 0;
foreach (KeyValuePair<TKey, List<TSource>> group in groups)
{
if (counter == nullCounter)
{
Grouping<TKey, TSource> nullGroup = new Grouping<TKey, TSource>(default(TKey), nullList);
yield return nullGroup;
counter++;
}
Grouping<TKey, TSource> grouping = new Grouping<TKey, TSource>(group.Key, group.Value);
yield return grouping;
counter++;
}
}
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();
Dictionary<TKey, List<TElement>> groups = new Dictionary<TKey, List<TElement>>();
List<TElement> nullList = new List<TElement>();
int counter = 0;
int nullCounter = -1;
foreach (TSource item in source)
{
TKey key = keySelector(item);
TElement element = elementSelector(item);
if (key == null)
{
nullList.Add(element);
if (nullCounter == -1)
{
nullCounter = counter;
counter++;
}
}
else
{
List<TElement> group = ContainsGroup<TKey, TElement>(groups, key, comparer);
if (group == null)
{
group = new List<TElement>();
groups.Add(key, group);
counter++;
}
group.Add(element);
}
}
counter = 0;
foreach (KeyValuePair<TKey, List<TElement>> group in groups)
{
if (counter == nullCounter)
{
Grouping<TKey, TElement> nullGroup = new Grouping<TKey, TElement>(default(TKey), nullList);
yield return nullGroup;
counter++;
}
Grouping<TKey, TElement> grouping = new Grouping<TKey, TElement>(group.Key, group.Value);
yield return grouping;
counter++;
}
}
#endregion
# region GroupJoin
public static IEnumerable<TResult> GroupJoin<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)
{
return GroupJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, null);
}
public static IEnumerable<TResult> GroupJoin<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)
{
if (outer == null || inner == null || outerKeySelector == null ||
innerKeySelector == null || resultSelector == null)
throw new ArgumentNullException();
if (comparer == null)
comparer = EqualityComparer<TKey>.Default;
Lookup<TKey, TInner> innerKeys = ToLookup<TInner, TKey>(inner, innerKeySelector, comparer);
/*Dictionary<K, List<U>> innerKeys = new Dictionary<K, List<U>> ();
foreach (U element in inner)
{
K innerKey = innerKeySelector (element);
if (!innerKeys.ContainsKey (innerKey))
innerKeys.Add (innerKey, new List<U> ());
innerKeys[innerKey].Add (element);
}*/
foreach (TOuter element in outer)
{
TKey outerKey = outerKeySelector(element);
if (innerKeys.Contains(outerKey))
yield return resultSelector(element, innerKeys[outerKey]);
}
}
#endregion
#region Intersect
public static IEnumerable<TSource> Intersect<TSource>(/*this*/ IEnumerable<TSource> first, IEnumerable<TSource> second)
{
if (first == null || second == null)
throw new ArgumentNullException();
List<TSource> items = new List<TSource>(Distinct(first));
bool[] marked = new bool[items.Count];
for (int i = 0; i < marked.Length; i++)
marked[i] = false;
foreach (TSource element in second)
{
int index = IndexOf(items, element);
if (index != -1)
marked[index] = true;
}
for (int i = 0; i < marked.Length; i++)
{
if (marked[i])
yield return items[i];
}
}
#endregion
# region Join
public static IEnumerable<TResult> Join<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)
{
if (outer == null || inner == null || outerKeySelector == null ||
innerKeySelector == null || resultSelector == null)
throw new ArgumentNullException();
if (comparer == null)
comparer = EqualityComparer<TKey>.Default;
Lookup<TKey, TInner> innerKeys = ToLookup<TInner, TKey>(inner, innerKeySelector, comparer);
/*Dictionary<K, List<U>> innerKeys = new Dictionary<K, List<U>> ();
foreach (U element in inner)
{
K innerKey = innerKeySelector (element);
if (!innerKeys.ContainsKey (innerKey))
innerKeys.Add (innerKey, new List<U> ());
innerKeys[innerKey].Add (element);
}*/
foreach (TOuter element in outer)
{
TKey outerKey = outerKeySelector(element);
if (innerKeys.Contains(outerKey))
{
foreach (TInner innerElement in innerKeys[outerKey])
yield return resultSelector(element, innerElement);
}
}
}
public static IEnumerable<TResult> Join<TOuter, TInner, TKey, TResult>(/*this*/ IEnumerable<TOuter> outer,
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);
}
# endregion
#region Last
public static TSource Last<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
bool noElements = true;
TSource lastElement = default(TSource);
foreach (TSource element in source)
{
if (noElements) noElements = false;
lastElement = element;
}
if (!noElements)
return lastElement;
else
throw new InvalidOperationException();
}
public static TSource Last<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, bool> predicate)
{
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;
}
}
if (!noElements)
return lastElement;
else
throw new InvalidOperationException();
}
#endregion
#region LastOrDefault
public static TSource LastOrDefault<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
TSource lastElement = default(TSource);
foreach (TSource element in source)
lastElement = element;
return lastElement;
}
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;
}
return lastElement;
}
#endregion
#region LongCount
public static long LongCount<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
long counter = 0;
foreach (TSource element in source)
counter++;
return counter;
}
public static long LongCount<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, bool> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
long counter = 0;
foreach (TSource element in source)
if (selector(element))
counter++;
return counter;
}
#endregion
#region Max
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static int? Max(/*this*/ IEnumerable<int?> 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);
}
public static long Max(/*this*/ IEnumerable<long> source)
{
if (source == null)
throw new ArgumentNullException();
long maximum = long.MinValue;
int counter = 0;
foreach (long element in source)
{
if (element > maximum)
maximum = element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
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);
}
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static double? Max(/*this*/ IEnumerable<double?> 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);
}
public static decimal Max(/*this*/ IEnumerable<decimal> source)
{
if (source == null)
throw new ArgumentNullException();
decimal maximum = decimal.MinValue;
int counter = 0;
foreach (decimal element in source)
{
if (element > maximum)
maximum = element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static decimal? Max(/*this*/ IEnumerable<decimal?> source)
{
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;
}
}
return (onlyNull ? null : maximum);
}
public static T Max<T>(/*this*/ IEnumerable<T> source)
{
if (source == null)
throw new ArgumentNullException();
bool notAssigned = true;
T maximum = default(T);
int counter = 0;
foreach (T element in source)
{
if (notAssigned)
{
maximum = element;
notAssigned = false;
}
else
{
int comparison;
if (element is IComparable<T>)
comparison = ((IComparable<T>)element).CompareTo(maximum);
else if (element is System.IComparable)
comparison = ((System.IComparable)element).CompareTo(maximum);
else
throw new ArgumentNullException();
if (comparison > 0)
maximum = element;
}
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static int Max<T>(/*this*/ IEnumerable<T> source,
Func<T, int> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
int maximum = int.MinValue;
int counter = 0;
foreach (T item in source)
{
int element = selector(item);
if (element > maximum)
maximum = element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static int? Max<T>(/*this*/ IEnumerable<T> source,
Func<T, int?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
bool onlyNull = true;
int? maximum = int.MinValue;
foreach (T item in source)
{
int? element = selector(item);
if (element.HasValue)
{
onlyNull = false;
if (element > maximum)
maximum = element;
}
}
return (onlyNull ? null : maximum);
}
public static long Max<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, long> 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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static long? Max<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, long?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static double Max<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, double> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
double maximum = double.MinValue;
int counter = 0;
foreach (TSource item in source)
{
double element = selector(item);
if (element > maximum)
maximum = element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static double? Max<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, double?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static decimal Max<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, decimal> 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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
public static decimal? Max<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, decimal?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static TResult Max<TSource, TResult>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TResult> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
bool notAssigned = true;
TResult maximum = default(TResult);
int counter = 0;
foreach (TSource item in source)
{
TResult element = selector(item);
if (notAssigned)
{
maximum = element;
notAssigned = false;
}
else
{
int comparison;
if (element is IComparable<TResult>)
comparison = ((IComparable<TResult>)element).CompareTo(maximum);
else if (element is System.IComparable)
comparison = ((System.IComparable)element).CompareTo(maximum);
else
throw new ArgumentNullException();
if (comparison > 0)
maximum = element;
}
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return maximum;
}
#endregion
#region Min
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
public static int? Min(/*this*/ IEnumerable<int?> 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);
}
public static long Min(/*this*/ IEnumerable<long> 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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
public static long? Min(/*this*/ IEnumerable<long?> 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);
}
public static double Min(/*this*/ IEnumerable<double> source)
{
if (source == null)
throw new ArgumentNullException();
double minimum = double.MaxValue;
int counter = 0;
foreach (double element in source)
{
if (element < minimum)
minimum = element;
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
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);
}
public static decimal Min(/*this*/ IEnumerable<decimal> source)
{
if (source == null)
throw new ArgumentNullException();
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;
}
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);
}
public static TSource Min<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException();
bool notAssigned = true;
TSource minimum = default(TSource);
int counter = 0;
foreach (TSource element in source)
{
if (notAssigned)
{
minimum = element;
notAssigned = false;
}
else
{
int comparison;
if (element is IComparable<TSource>)
comparison = ((IComparable<TSource>)element).CompareTo(minimum);
else if (element is System.IComparable)
comparison = ((System.IComparable)element).CompareTo(minimum);
else
throw new ArgumentNullException();
if (comparison < 0)
minimum = element;
}
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
public static int? Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, int?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static long Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, long> 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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
public static long? Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, long?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static double Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, double> 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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
public static double? Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, double?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static decimal Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, decimal> 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++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
public static decimal? Min<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, decimal?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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);
}
public static TResult Min<TSource, TResult>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TResult> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
bool notAssigned = true;
TResult minimum = default(TResult);
int counter = 0;
foreach (TSource item in source)
{
TResult element = selector(item);
if (notAssigned)
{
minimum = element;
notAssigned = false;
}
else
{
int comparison;
if (element is IComparable<TResult>)
comparison = ((IComparable<TResult>)element).CompareTo(minimum);
else if (element is System.IComparable)
comparison = ((System.IComparable)element).CompareTo(minimum);
else
throw new ArgumentNullException();
if (comparison < 0)
minimum = element;
}
counter++;
}
if (counter == 0)
throw new InvalidOperationException();
else
return minimum;
}
#endregion
#region OfType
public static IEnumerable<TSource> OfType<TSource>(/*this*/ IEnumerable source)
{
if (source == null)
throw new ArgumentNullException();
foreach (object element in source)
if (element is TSource)
yield return (TSource)element;
}
#endregion
#region OrderBy
public static OrderedSequence<TSource> OrderBy<TSource, TKey>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TKey> keySelector)
{
return OrderBy<TSource, TKey>(source, keySelector, null);
}
public static OrderedSequence<TSource> OrderBy<TSource, TKey>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey> comparer)
{
if (source == null || keySelector == null)
throw new ArgumentNullException();
return new InternalOrderedSequence<TSource, TKey>(
source, keySelector, (comparer ?? Comparer<TKey>.Default), false, null);
}
#endregion
#region OrderByDescending
public static OrderedSequence<TSource> OrderByDescending<TSource, TKey>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TKey> keySelector)
{
return OrderByDescending<TSource, TKey>(source, keySelector, null);
}
public static OrderedSequence<TSource> OrderByDescending<TSource, TKey>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
{
if (source == null || keySelector == null)
throw new ArgumentNullException();
return new InternalOrderedSequence<TSource, TKey>(
source, keySelector, (comparer ?? Comparer<TKey>.Default), true, null);
}
#endregion
#region Range
public static IEnumerable<int> Range(int start, int count)
{
if (count < 0 || (start + count - 1) > int.MaxValue)
throw new ArgumentOutOfRangeException();
for (int i = start; i < (start + count - 1); i++)
yield return i;
}
#endregion
#region Repeat
public static IEnumerable<TResult> Repeat<TResult>(TResult element, int count)
{
if (count < 0)
throw new ArgumentOutOfRangeException();
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();
List<TSource> list = new List<TSource>(source);
list.Reverse();
return list;
}
#endregion
#region Select
public static IEnumerable<TResult> Select<TSource, TResult>(/*this*/ IEnumerable<TSource> source,
Func<TSource, TResult> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
foreach (TSource element in source)
yield return selector(element);
}
public static IEnumerable<TResult> Select<TSource, TResult>(/*this*/ IEnumerable<TSource> source,
Func<TSource, int, TResult> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
int counter = 0;
foreach (TSource element in source)
{
yield return selector(element, counter);
counter++;
}
}
#endregion
#region SelectMany
public static IEnumerable<TResult> SelectMany<TSource, TResult>(/*this*/ IEnumerable<TSource> source,
Func<TSource, IEnumerable<TResult>> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
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)
{
if (source == null || selector == null)
throw new ArgumentNullException();
int counter = 0;
foreach (TSource element in source)
{
foreach (TResult item in selector(element, counter))
yield return item;
counter++;
}
}
#endregion
#region Single
public static TSource Single<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;
}
if (otherElement)
return singleElement;
else
throw new InvalidOperationException();
}
public static TSource Single<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;
}
}
if (otherElement)
return singleElement;
else
throw new InvalidOperationException();
}
#endregion
#region SingleOrDefault
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;
}
return singleElement;
}
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;
}
}
return singleElement;
}
#endregion
#region Skip
public static IEnumerable<TSource> Skip<TSource>(/*this*/ IEnumerable<TSource> source, int count)
{
if (source == null)
throw new NotSupportedException();
int i = 0;
foreach (TSource e in source)
{
if (++i < count)
continue;
yield return e;
}
}
#endregion
#region SkipWhile
public static IEnumerable<T> SkipWhile<T>(
IEnumerable<T> source,
Func<T, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
bool yield = false;
foreach (T element in source)
{
if (yield)
yield return element;
else
if (!predicate(element))
{
yield return element;
yield = true;
}
}
}
public static IEnumerable<TSource> SkipWhile<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, int, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
int counter = 0;
bool yield = false;
foreach (TSource element in source)
{
if (yield)
yield return element;
else
if (!predicate(element, counter))
{
yield return element;
yield = true;
}
counter++;
}
}
#endregion
#region Sum
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;
return sum;
}
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)
sum += selector(element);
return sum;
}
public static int? Sum(/*this*/ IEnumerable<int?> source)
{
if (source == null)
throw new ArgumentNullException();
int? sum = 0;
foreach (int? element in source)
if (element.HasValue)
sum += element.Value;
return sum;
}
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;
}
return sum;
}
public static long Sum(/*this*/ IEnumerable<long> source)
{
if (source == null)
throw new ArgumentNullException();
long sum = 0;
foreach (long element in source)
sum += element;
return sum;
}
public static long Sum<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, long> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
long sum = 0;
foreach (TSource element in source)
sum += selector(element);
return sum;
}
public static long? Sum(/*this*/ IEnumerable<long?> source)
{
if (source == null)
throw new ArgumentNullException();
long? sum = 0;
foreach (long? element in source)
if (element.HasValue)
sum += element.Value;
return sum;
}
public static long? Sum<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, long?> selector)
{
if (source == null || selector == null)
throw new ArgumentNullException();
long? sum = 0;
foreach (TSource element in source)
{
long? item = selector(element);
if (item.HasValue)
sum += item.Value;
}
return sum;
}
public static double Sum(/*this*/ IEnumerable<double> source)
{
if (source == null)
throw new ArgumentNullException();
double sum = 0;
foreach (double element in source)
sum += element;
return sum;
}
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);
return sum;
}
public static double? Sum(/*this*/ IEnumerable<double?> source)
{
if (source == null)
throw new ArgumentNullException();
double? sum = 0;
foreach (double? element in source)
if (element.HasValue)
sum += element.Value;
return sum;
}
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)
{
double? item = selector(element);
if (item.HasValue)
sum += item.Value;
}
return sum;
}
public static decimal Sum(/*this*/ IEnumerable<decimal> source)
{
if (source == null)
throw new ArgumentNullException();
decimal sum = 0;
foreach (decimal element in source)
sum += element;
return sum;
}
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);
return sum;
}
public static decimal? Sum(/*this*/ IEnumerable<decimal?> source)
{
if (source == null)
throw new ArgumentNullException();
decimal? sum = 0;
foreach (decimal? element in source)
if (element.HasValue)
sum += element.Value;
return sum;
}
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)
{
decimal? item = selector(element);
if (item.HasValue)
sum += item.Value;
}
return sum;
}
#endregion
#region Take
public static IEnumerable<T> Take<T>(/*this*/ IEnumerable<T> source, int count)
{
if (source == null)
throw new ArgumentNullException();
if (count <= 0)
yield break;
else
{
int counter = 0;
foreach (T element in source)
{
yield return element;
counter++;
if (counter == count)
yield break;
}
}
}
#endregion
#region TakeWhile
public static IEnumerable<T> TakeWhile<T>(/*this*/ IEnumerable<T> source, Func<T, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
foreach (T element in source)
{
if (predicate(element))
yield return element;
else
yield break;
}
}
public static IEnumerable<TSource> TakeWhile<TSource>(/*this*/ IEnumerable<TSource> source, Func<TSource, int, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
int counter = 0;
foreach (TSource element in source)
{
if (predicate(element, counter))
yield return element;
else
yield break;
counter++;
}
}
#endregion
#region ThenBy
public static OrderedSequence<TSource> ThenBy<TSource, TKey>(/*this*/ OrderedSequence<TSource> source, Func<TSource, TKey> keySelector)
{
return ThenBy<TSource, TKey>(source, keySelector, null);
}
public static OrderedSequence<TSource> ThenBy<TSource, TKey>(/*this*/ OrderedSequence<TSource> source,
Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
{
if (source == null || keySelector == null)
throw new ArgumentNullException();
return new InternalOrderedSequence<TSource, TKey>(
source, keySelector, (comparer ?? Comparer<TKey>.Default), false, source);
}
#endregion
#region ThenByDescending
public static OrderedSequence<TSource> ThenByDescending<TSource, TKey>(/*this*/ OrderedSequence<TSource> source,
Func<TSource, TKey> keySelector)
{
return ThenByDescending<TSource, TKey>(source, keySelector, null);
}
public static OrderedSequence<TSource> ThenByDescending<TSource, TKey>(/*this*/ OrderedSequence<TSource> source,
Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
{
if (source == null || keySelector == null)
throw new ArgumentNullException();
return new InternalOrderedSequence<TSource, TKey>(
source, keySelector, (comparer ?? Comparer<TKey>.Default), true, source);
}
#endregion
#region ToArray
public static T[] ToArray<T> (/*this*/ IEnumerable<T> source)
{
if (source == null)
throw new ArgumentNullException ();
List<T> list = new List<T> (source);
return list.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)
{
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)
{
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)
{
dict.Add(keySelector(e), elementSelector(e));
}
return dict;
}
#endregion
#region ToList
public static List<TSource> ToList<TSource>(/*this*/ IEnumerable<TSource> source)
{
if (source == null)
throw new ArgumentNullException("source");
return new List<TSource>(source);
}
#endregion
#region ToLookup
public static Lookup<TKey, TSource> ToLookup<TSource, TKey>(/*this*/ IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
{
return ToLookup<TSource, TKey>(source, keySelector, null);
}
public static Lookup<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);
}
public static Lookup<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,
Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
{
if (source == null || keySelector == null || elementSelector == null)
throw new ArgumentNullException();
Dictionary<TKey, List<TElement>> dictionary = new Dictionary<TKey, List<TElement>>(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<TElement>());
dictionary[key].Add(elementSelector(element));
}
return new Lookup<TKey, TElement>(dictionary);
}
#endregion
#region ToSequence
public static IEnumerable<T> ToSequence<T>(/*this*/ IEnumerable<T> source)
{
return (IEnumerable<T>)source;
}
#endregion
#region Union
public static IEnumerable<T> Union<T>(/*this*/ IEnumerable<T> first, IEnumerable<T> second)
{
if (first == null || second == null)
throw new ArgumentNullException();
List<T> items = new List<T>();
foreach (T element in first)
{
if (IndexOf(items, element) == -1)
{
items.Add(element);
yield return element;
}
}
foreach (T element in second)
{
if (IndexOf(items, element) == -1)
{
items.Add(element);
yield return element;
}
}
}
#endregion
#region Where
public static IEnumerable<TSource> Where<TSource>(/*this*/ IEnumerable<TSource> source,
Func<TSource, bool> predicate)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
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)
{
if (source == null || predicate == null)
throw new ArgumentNullException();
int counter = 0;
foreach (TSource element in source)
{
if (predicate(element, counter))
yield return 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
public 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;
}
public static int IndexOf<T>(/*this*/ IEnumerable<T> source, T item)
{
return IndexOf<T>(source, item, null);
}
#endregion
#region ToReadOnlyCollection
internal static ReadOnlyCollection<TSource> ToReadOnlyCollection<TSource>(IEnumerable<TSource> source)
{
if (source == null)
return new ReadOnlyCollection<TSource>(new List<TSource>());
if (typeof(ReadOnlyCollection<TSource>).IsInstanceOfType(source))
return source as ReadOnlyCollection<TSource>;
return new ReadOnlyCollection<TSource>(ToArray<TSource>(source));
}
#endregion
}
}
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