如何检查 ArrayList 是否包含 2 个值? [英] How to Check if an ArrayList Contain 2 values?

问题描述

有什么方法可以检查集合是否包含一个或多个值，其性能比使用 contains 循环两次更好吗?

is there any way to check if a collection contain a value or more with better performance than looping twice with contains?

换句话说就是看起来像这样的东西

in other meaning something that would look like this

person.contains("Joe" || "Jasha");

推荐答案

ArrayList.contains() 的实现循环遍历每个元素并进行 equals() 测试，所以调用 .contains() 两次效率低下.

The implementation of ArrayList.contains() loops through every element and does an equals() test, so calling .contains() twice is inefficient.

您可以编写自己的循环，使用已编译的正则表达式同时检查两者 模式同时查找任一名称:

You could write your own loop that check both at once using a compiled regex Pattern that looks for either name at the same time:

Pattern p = Pattern.compile("Joe|Jasha");
boolean found = false;
for (String s : person) {
    if (p.matcher(s).find()) {
        found = true;
        break;
    }
}

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