随机迭代ArrayList< Integer>.在Java中 [英] Randomly iterate over ArrayList<Integer> in Java

问题描述

似乎是一个非常基本的问题.我有一个 ArrayList< Integer>al ，我想对其进行迭代.通常，

Seems a very basic question. I've an ArrayList<Integer> al and I would like to iterate over it. Normally,

for(int i : al) {
    // some code
}

可以解决问题.但是我的要求是不按顺序进行迭代，而是随机进行.

does the trick. But my requirement is to iterate not in sequence but randomly.

推荐答案

您可以使用

You can use Collections.shuffle() on the list.

请注意，这会随机排列列表，因此，如果顺序很重要，则应制作一个副本(并随机排​​列副本).

Note that this will shuffle the list itself, so if order is important you should make a copy of it (and shuffle the copy).

List<Customer> newList = new ArrayList<>( oldList ) ;
Collections.shuffle( newList ) ;

或者，您可以创建一个包含元素 0-List.size()-1 的随机数组，并使用这些元素作为索引来访问 List 中的随机"元素

Alternatively you could create a random array which has elements 0 - List.size()-1 and using those as indices to access "random" elements in the List.

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