如何检查一组项目中是否存在元素？ [英] How can I check if an element exists in a Set of items?

问题描述

在Java中的 if 语句中，如何检查对象是否存在于一组项目中。例如。
在这种情况下，我需要验证水果是苹果，橙子还是香蕉。

In an if statement in Java how can I check whether an object exists in a set of items. E.g. In this scenario i need to validate that the fruit will be an apple, orange or banana.

if (fruitname in ["APPLE", "ORANGES", "GRAPES"]) {
    //Do something
}

这是一个非常微不足道的事情，但我无法找到一个简短而简洁的方法来实现这一目标。

It's a very trivial thing but I couldn't figure out a short and concise way to accomplish this.

推荐答案

static final List<String> fruit = Arrays.asList("APPLE", "ORANGES", "GRAPES");

if (fruit.contains(fruitname))

如果你的清单是更大，一组会更有效。

If your list was much larger, a set would be more efficient.

static final Set<String> fruit = new HashSet<String>(
       Arrays.asList("APPLE", "ORANGES", "GRAPES", /*many more*/));

这篇关于如何检查一组项目中是否存在元素？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！