的IEqualityComparer为SequenceEqual [英] IEqualityComparer for SequenceEqual

问题描述

在C＃中，有一个的IEqualityComparer＆LT; IEnumerable的＆GT; 使用的 SequenceEqual 法确定的平等

In C#, is there a IEqualityComparer<IEnumerable> that uses the SequenceEqual method to determine equality?

推荐答案

有没有这样的比较器在.NET Framework中，但你可以创建一个：

There is no such comparer in .NET Framework, but you can create one:

public class IEnumerableComparer<T> : IEqualityComparer<IEnumerable<T>>
{
    public bool Equals(IEnumerable<T> x, IEnumerable<T> y)
    {
        return Object.ReferenceEquals(x, y) || (x != null && y != null && x.SequenceEqual(y));
    }

    public int GetHashCode(IEnumerable<T> obj)
    {
        if (obj == null)
            return 0;

        // Will not throw an OverflowException
        unchecked
        {
            return obj.Select(e => e.GetHashCode()).Aggregate(17, (a, b) => 23 * a + b);
        }
    }
}

在上面的code，我遍历了 GetHash code 集合中的所有项目。我不知道这是否是最明智的解决方案，但是这就是在内部完成<一个href="http://referencesource.microsoft.com/#System.Core/System/Collections/Generic/HashSetEqualityComparer.cs"相对=nofollow> HashSetEqualityComparer 。

In the above code, I iterate over all items of the collection in the GetHashCode. I don't know if it's the wisest solution but this what is done in the internal HashSetEqualityComparer.

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