查找重复的字符串数组 [英] Finding Duplicate String Arrays

问题描述

我有一个很大的字符串数组列表，并且在这个List<string[]>中，可以存在具有所有相同值(并且可能具有不同索引)的数组.我正在寻找并计数这些重复字符串数组，并具有一个Dictionary<string[], int>，其中int是计数(但是，如果有比使用字典更好的方法，我想听听一下).有人对如何实现这一目标有任何建议吗?任何和所有输入非常感谢，谢谢！

I have a large list of string arrays, and within this List<string[]> there can be arrays with all same values (and possibly with different indexes). I'm looking to find and count these duplicate string arrays and have a Dictionary<string[], int> with int being the count (however if there is a better way than using a dictionary I would be interested in hearing). Does anyone have any advice on how to achieve this? Any and all input is very appreciated, thanks!

推荐答案

您可以使用linq GroupBy和IEqualityComparer来比较string[]

You can use linq GroupBy with a IEqualityComparer to compare the string[]

var items = new List<string[]>() 
    { 
        new []{"1", "2", "3" ,"4" }, 
        new []{"4","3", "2", "1"},
        new []{"1", "2"}
    };

var results = items
        .GroupBy(i => i, new UnorderedEnumerableComparer<string>())
        .ToDictionary(g => g.Key, g => g.Count());

无序列表的IEqualityComparer

public class UnorderedEnumerableComparer<T> : IEqualityComparer<IEnumerable<T>>
{
    public bool Equals(IEnumerable<T> x, IEnumerable<T> y)
    {
        return x.OrderBy(i => i).SequenceEqual(y.OrderBy(i => i));
    }
    // Just the count of the array, 
    // it violates the rule of hash code but should be fine here
    public int GetHashCode(IEnumerable<T> obj)
    {
        return obj.Count();
    }
}

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