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Lazily enumerate source enumerable 

Don't consume with ToArray() before iterating and yielding results back. This decreases allocations
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Oliver Booth 2021-07-20 17:15:10 +01:00
parent 35a9b31be7
commit d6e8471239
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1 changed files with 24 additions and 11 deletions
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35
X10D/src/EnumerableExtensions/EnumerableExtensions.cs
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@ -1,6 +1,5 @@
using System;
using System;
using System.Collections.Generic;
using System.Linq;
namespace X10D
{
@ -23,24 +22,38 @@ namespace X10D
}
/// <summary>
/// Splits <paramref name="value" /> into chunks of size <paramref name="chunkSize" />.
/// Splits <paramref name="source" /> into chunks of size <paramref name="chunkSize" />.
/// </summary>
/// <typeparam name="T">Any type.</typeparam>
/// <param name="value">The collection to split.</param>
/// <param name="source">The collection to split.</param>
/// <param name="chunkSize">The maximum length of the nested collection.</param>
/// <returns>
/// An <see cref="IEnumerable{T}" /> containing an <see cref="IEnumerable{T}" /> of <typeparamref name="T" />
/// whose lengths are no greater than <paramref name="chunkSize" />.
/// </returns>
public static IEnumerable<IEnumerable<T>> Split<T>(this IEnumerable<T> value, int chunkSize)
public static IEnumerable<IEnumerable<T>> Split<T>(this IEnumerable<T> source, int chunkSize)
{
var enumerable = value.ToArray();
var count = enumerable.LongLength;
chunkSize = chunkSize.Clamp(1, enumerable.Length);
for (var i = 0; i < (int)(count / chunkSize); i++)
if (source is null)
{
yield return enumerable.Skip(i * chunkSize).Take(chunkSize);
throw new ArgumentNullException(nameof(source));
}
var buffer = new List<T>(chunkSize);
foreach (var item in source)
{
buffer.Add(item);
if (buffer.Count >= chunkSize)
{
yield return buffer;
buffer.Clear();
}
}
if (buffer.Count > 0)
{
yield return buffer;
}
}
}