具有多重比较的更清洁的 if 语句 [英] A cleaner if statement with multiple comparisons

问题描述

当你有很多术语时，下面的语句看起来很混乱:

The following statement just looks very messy when you have a lot of terms:

if(a.equals("x") || a.equals("y") || a.equals("z") || Any number of terms...... )
    //Do something

是否有更简洁的方法来执行相同的操作，我希望我的代码尽可能具有可读性.

Is there a cleaner way of performing the same action, I would like my code to be as readable as possible.

注意:x、y 和 z 只是任何长度的任何字符串的占位符.在 if 条件中，这里可能有 20 个可变长度的字符串术语，每个术语都被 OR'd 在一起

NOTE: x, y and z are just placeholders for any string of any length. There could be 20 string terms here of variable length in if condition each being OR'd together

推荐答案

Set<String> stuff = new HashSet<String>();
stuff.add("x");
stuff.add("y");
stuff.add("z");
if(stuff.contains(a)) {
    //stuff
}

如果这是一个紧密循环，您可以使用静态 Set.

If this is a tight loop you can use a static Set.

static Set<String> stuff;
static {
    stuff = new HashSet<String>();
    stuff.add("x");
    stuff.add("y");
    stuff.add("z");
}

//Somewhere else in the cosmos

if(stuff.contains(a)) {
    //stuff
}

如果您想在不看的时候更加确定没有任何修改.

And if you want to be extra sure nothing is getting modified while you're not looking.

Set<String> test = Collections.unmodifiableSet(new HashSet<String>() {
        {
            add("x");
            add("y");
            add("z");
        }
    });

如果您只想为一些硬编码条件获得一些逻辑，那么 switch 或 if 语句之一与换行符解决方案可能会更好.但是，如果您有很多条件，那么最好将您的配置与逻辑分开.

If you just want to get some logic in there for a handful of hard coded conditions then one of the switch or if statement with newlines solutions might be better. But if you have a lot of conditions then it might be good to separate your configuration from logic.

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