如何获取数组的所有子集? [英] How to get all subsets of an array?

问题描述

给定一个数组:[dog, cat, mouse]

最优雅的创作方式是什么:

what is the most elegant way to create:

[,,]
[,,mouse]
[,cat,]
[,cat,mouse]
[dog,,]
[dog,,mouse]
[dog,cat,]
[dog,cat,mouse]

我需要它来处理任何大小的数组.

I need this to work for any sized array.

这本质上是一个二进制计数器，其中数组索引代表位.这大概可以让我使用一些按位运算来计数，但我看不到将其转换为数组索引的好方法.

This is essentially a binary counter, where array indices represent bits. This presumably lets me use some bitwise operation to count, but I can't see a nice way of translating this to array indices though.

推荐答案

 string[] source = new string[] { "dog", "cat", "mouse" };
 for (int i = 0; i < Math.Pow(2, source.Length); i++)
 {
     string[] combination = new string[source.Length];
     for (int j = 0; j < source.Length; j++)
     {
         if ((i & (1 << (source.Length - j - 1))) != 0)
         {
             combination[j] = source[j];
         }
    }
    Console.WriteLine("[{0}, {1}, {2}]", combination[0], combination[1], combination[2]);
}

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