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stephentoubstephentoub
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Add LINQ Shuffle (#112173)
1 parent f810340 commit 4008f82

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+982
-122
lines changed

‎src/libraries/System.Linq.AsyncEnumerable/ref/System.Linq.AsyncEnumerable.cs

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@@ -132,6 +132,7 @@ public static partial class AsyncEnumerable
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public static System.Collections.Generic.IAsyncEnumerable<TResult> Select<TSource, TResult>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Func<TSource, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<TResult>> selector) { throw null; }
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public static System.Collections.Generic.IAsyncEnumerable<TResult> Select<TSource, TResult>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Func<TSource, TResult> selector) { throw null; }
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public static System.Threading.Tasks.ValueTask<bool> SequenceEqualAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> first, System.Collections.Generic.IAsyncEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource>? comparer = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) { throw null; }
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public static System.Collections.Generic.IAsyncEnumerable<TSource> Shuffle<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source) { throw null; }
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public static System.Threading.Tasks.ValueTask<TSource> SingleAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Func<TSource, bool> predicate, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) { throw null; }
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public static System.Threading.Tasks.ValueTask<TSource> SingleAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Func<TSource, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<bool>> predicate, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) { throw null; }
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public static System.Threading.Tasks.ValueTask<TSource> SingleAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) { throw null; }

‎src/libraries/System.Linq.AsyncEnumerable/src/System.Linq.AsyncEnumerable.csproj

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@@ -12,6 +12,7 @@
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</PropertyGroup>
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<ItemGroup>
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<Compile Include="System\Linq\Shuffle.cs" />
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<Compile Include="System\Linq\SkipLast.cs" />
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<Compile Include="System\Linq\SkipWhile.cs" />
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<Compile Include="System\Linq\Append.cs" />

‎src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/Shuffle.cs

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@@ -0,0 +1,59 @@
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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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using System.Runtime.CompilerServices;
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using System.Threading;
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namespace System.Linq
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{
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public static partial class AsyncEnumerable
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{
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#if !NET
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[ThreadStatic]
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private static Random? t_random;
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#endif
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/// <summary>Shuffles the order of the elements of a sequence.</summary>
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/// <typeparam name="TSource">The type of the elements of <paramref name="source"/>.</typeparam>
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/// <param name="source">A sequence of values to shuffle.</param>
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/// <returns>A sequence whose elements correspond to those of the input sequence in randomized order.</returns>
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/// <remarks>Randomization is performed using a non-cryptographically-secure random number generator.</remarks>
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public static IAsyncEnumerable<TSource> Shuffle<TSource>(
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this IAsyncEnumerable<TSource> source)
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{
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ThrowHelper.ThrowIfNull(source);
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return Impl(source, default);
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static async IAsyncEnumerable<TSource> Impl(
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IAsyncEnumerable<TSource> source,
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[EnumeratorCancellation] CancellationToken cancellationToken)
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{
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TSource[] array = await source.ToArrayAsync(cancellationToken).ConfigureAwait(false);
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#if NET
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Random.Shared.Shuffle(array);
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#else
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Random random = t_random ??= new Random(Environment.TickCount ^ Environment.CurrentManagedThreadId);
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int n = array.Length;
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for (int i = 0; i < n - 1; i++)
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{
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int j = random.Next(i, n);
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if (j != i)
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{
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TSource temp = array[i];
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array[i] = array[j];
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array[j] = temp;
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}
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}
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#endif
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for (int i = 0; i < array.Length; i++)
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{
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yield return array[i];
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}
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}
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}
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}
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}

‎src/libraries/System.Linq.AsyncEnumerable/tests/ShuffleTests.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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using System.Threading;
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using System.Threading.Tasks;
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using Xunit;
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namespace System.Linq.Tests
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{
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public class ShuffleTests : AsyncEnumerableTests
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{
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[Fact]
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public void InvalidInputs_Throws()
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{
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AssertExtensions.Throws<ArgumentNullException>("source", () => AsyncEnumerable.Shuffle<int>(null));
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}
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[Theory]
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[InlineData(new int[0])]
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[InlineData(new int[] { 1 })]
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[InlineData(new int[] { 2, 4, 8 })]
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[InlineData(new int[] { -1, 2, 5, 6, 7, 8 })]
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public async Task VariousValues_ContainsAllInputValues(int[] values)
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{
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foreach (IAsyncEnumerable<int> source in CreateSources(values))
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{
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int[] shuffled = await source.Shuffle().ToArrayAsync();
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Array.Sort(shuffled);
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Assert.Equal(values, shuffled);
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}
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}
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[Fact]
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public async Task ToArrayAsync_ElementsAreRandomized()
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{
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// The chance that shuffling a thousand elements produces the same order twice is infinitesimal.
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int length = 1000;
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foreach (IAsyncEnumerable<int> source in CreateSources(Enumerable.Range(0, length).ToArray()))
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{
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int[] first = await source.Shuffle().ToArrayAsync();
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int[] second = await source.Shuffle().ToArrayAsync();
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Assert.Equal(length, first.Length);
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Assert.Equal(length, second.Length);
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Assert.NotEqual(first, second);
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}
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}
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[Fact]
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public async Task Cancellation_Cancels()
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{
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IAsyncEnumerable<int> source = CreateSource(2, 4, 8, 16);
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await Assert.ThrowsAsync<OperationCanceledException>(async () =>
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{
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await ConsumeAsync(source.Shuffle().WithCancellation(new CancellationToken(true)));
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});
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}
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[Fact]
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public async Task InterfaceCalls_ExpectedCounts()
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{
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TrackingAsyncEnumerable<int> source = CreateSource(2, 4, 8, 16).Track();
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await ConsumeAsync(source.Shuffle());
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Assert.Equal(5, source.MoveNextAsyncCount);
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Assert.Equal(4, source.CurrentCount);
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Assert.Equal(1, source.DisposeAsyncCount);
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}
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}
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}

‎src/libraries/System.Linq.AsyncEnumerable/tests/System.Linq.AsyncEnumerable.Tests.csproj

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@@ -10,6 +10,7 @@
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<Compile Include="ElementAtOrDefaultAsyncTests.cs" />
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<Compile Include="ElementAtAsyncTests.cs" />
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<Compile Include="GroupByTests.cs" />
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<Compile Include="ShuffleTests.cs" />
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<Compile Include="SingleOrDefaultAsyncTests.cs" />
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<Compile Include="SingleAsyncTests.cs" />
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<Compile Include="LastOrDefaultAsyncTests.cs" />

‎src/libraries/System.Linq.Queryable/ref/System.Linq.Queryable.cs

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@@ -158,6 +158,7 @@ public static partial class Queryable
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public static System.Linq.IQueryable<TResult> Select<TSource, TResult>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<System.Func<TSource, TResult>> selector) { throw null; }
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public static bool SequenceEqual<TSource>(this System.Linq.IQueryable<TSource> source1, System.Collections.Generic.IEnumerable<TSource> source2) { throw null; }
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public static bool SequenceEqual<TSource>(this System.Linq.IQueryable<TSource> source1, System.Collections.Generic.IEnumerable<TSource> source2, System.Collections.Generic.IEqualityComparer<TSource>? comparer) { throw null; }
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public static System.Linq.IQueryable<TSource> Shuffle<TSource>(this System.Linq.IQueryable<TSource> source) { throw null; }
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public static TSource? SingleOrDefault<TSource>(this System.Linq.IQueryable<TSource> source) { throw null; }
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public static TSource? SingleOrDefault<TSource>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<System.Func<TSource, bool>> predicate) { throw null; }
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public static TSource SingleOrDefault<TSource>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<System.Func<TSource, bool>> predicate, TSource defaultValue) { throw null; }

‎src/libraries/System.Linq.Queryable/src/System/Linq/Queryable.cs

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@@ -1587,6 +1587,18 @@ public static bool SequenceEqual<TSource>(this IQueryable<TSource> source1, IEnu
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Expression.Constant(comparer, typeof(IEqualityComparer<TSource>))));
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}
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[DynamicDependency("Shuffle`1", typeof(Enumerable))]
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public static IQueryable<TSource> Shuffle<TSource>(this IQueryable<TSource> source)
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{
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ArgumentNullException.ThrowIfNull(source);
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return source.Provider.CreateQuery<TSource>(
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Expression.Call(
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null,
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new Func<IQueryable<TSource>, IQueryable<TSource>>(Shuffle).Method,
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source.Expression));
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}
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[DynamicDependency("Any`1", typeof(Enumerable))]
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public static bool Any<TSource>(this IQueryable<TSource> source)
15921604
{

‎src/libraries/System.Linq.Queryable/tests/ShuffleTests.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using Xunit;
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namespace System.Linq.Tests
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{
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public class ShuffleTests : EnumerableBasedTests
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{
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[Fact]
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public void InvalidArguments()
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{
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AssertExtensions.Throws<ArgumentNullException>("source", () => ((IQueryable<string>)null).Shuffle());
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}
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[Fact]
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public void ProducesAllElements()
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{
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int[] shuffled = Enumerable.Range(0, 1000).AsQueryable().Shuffle().ToArray();
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Array.Sort(shuffled);
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Assert.Equal(Enumerable.Range(0, shuffled.Length), shuffled);
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}
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[Fact]
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public void ElementsAreRandomized()
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{
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// The chance that shuffling a thousand elements produces the same order twice is infinitesimal.
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const int Length = 1000;
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IQueryable<int> source = Enumerable.Range(0, Length).AsQueryable().Shuffle();
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int[] first = source.ToArray();
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int[] second = source.ToArray();
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Assert.Equal(Length, first.Length);
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Assert.Equal(Length, second.Length);
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Assert.NotEqual(first, second);
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}
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}
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}

‎src/libraries/System.Linq.Queryable/tests/System.Linq.Queryable.Tests.csproj

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@@ -31,6 +31,7 @@
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<Compile Include="JoinTests.cs" />
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<Compile Include="LastOrDefaultTests.cs" />
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<Compile Include="LastTests.cs" />
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<Compile Include="ShuffleTests.cs" />
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<Compile Include="RightJoinTests.cs" />
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<Compile Include="LongCountTests.cs" />
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<Compile Include="MaxTests.cs" />
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<Compile Include="UnionTests.cs" />
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<Compile Include="WhereTests.cs" />
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<Compile Include="ZipTests.cs" />
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<Compile Include="$(CommonTestPath)System\Linq\SkipTakeData.cs"
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Link="Common\System\Linq\SkipTakeData.cs" />
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<Compile Include="$(CommonTestPath)System\Linq\SkipTakeData.cs" Link="Common\System\Linq\SkipTakeData.cs" />
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</ItemGroup>
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</Project>

‎src/libraries/System.Linq/ref/System.Linq.cs

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// Changes to this file must follow the https://aka.ms/api-review process.
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// ------------------------------------------------------------------------------
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using System.Collections.Generic;
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namespace System.Linq
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{
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public static partial class Enumerable
@@ -172,6 +174,7 @@ public static System.Collections.Generic.IEnumerable<
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public static System.Collections.Generic.IEnumerable<TResult> Select<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TResult> selector) { throw null; }
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public static bool SequenceEqual<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) { throw null; }
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public static bool SequenceEqual<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource>? comparer) { throw null; }
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public static System.Collections.Generic.IEnumerable<TSource> Shuffle<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) { throw null; }
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public static TSource? SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) { throw null; }
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public static TSource SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource defaultValue) { throw null; }
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public static TSource? SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) { throw null; }

‎src/libraries/System.Linq/src/System.Linq.csproj

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<Compile Include="System\Linq\Range.SpeedOpt.cs" />
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<Compile Include="System\Linq\Repeat.cs" />
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<Compile Include="System\Linq\Repeat.SpeedOpt.cs" />
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<Compile Include="System\Linq\Shuffle.SpeedOpt.cs" />
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<Compile Include="System\Linq\Shuffle.cs" />
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<Compile Include="System\Linq\Reverse.cs" />
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<Compile Include="System\Linq\Reverse.SpeedOpt.cs" />
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<Compile Include="System\Linq\RightJoin.cs" />

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