看看String包含在数组中的元素 [英] See if String Contains An Element in an Array

问题描述

我试图去通过运营商数组，看是否运营商之一位于字符串。

I am trying to go through an array of Operators to see if one of the operators is located in the String.

例如：

String[] OPERATORS    = { "<", "<=", ... };
String line = "a <= b < c ";

我怎么会去通过一个循环，检查是否操作是字符串中去？

How would I go about going through a loop that checks to see if an operator is in the string?

另外，说我的方法发现，＆LT;位于字符串＆LT; =

Also, say my method found that "<" is located in the string at "<= "

不过，我寻找的实际字符串＆LT; = 。
我怎么会去占呢？

However, I am looking for the actual string " <= ". How would I go about accounting for that?

推荐答案

我会用一个正则表达式，而不是让所有的运营商数组。此外，确保运营商的确切顺序在你的正则表达式，即＆LT; = 前应＆LT; 同样， == 前应 = ：

I would use a regex instead of having array of all the operators. Also, make sure the operators are in the exact order in your regex, i.e., <= should be before <, similarly, == should be before =:

String regex = "<=|<|>=|>|==|=|\\+|-";

String line = "a <= b < c ";

Matcher matcher = Pattern.compile(regex).matcher(line);

while (matcher.find()) {
    System.out.println(matcher.start() + " : " + matcher.group());
} 

输出

2 : <=
7 : <

的诀窍是，正则表达式匹配前＆LT; 的＆LT; = ，将已经通过＆LT匹配= ，因为它来自前＆LT;

The trick is that, before the regex matches <, of <=, it will already be matched by <=, as it comes before <.

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