Java正则表达式不区分大小写不起作用 [英] Java regex case insensitivity not working

问题描述

我正在尝试使用正则表达式使用以下程序删除字符串中的某些单词.它可以正确删除，但只考虑大小写.如何使其不区分大小写.我将(?1)保留在 replaceAll 方法中，但是没有用.

I'm trying to remove some words in a string using regex using below program. Its removing properly but its considering only case sensitive. How to make it as case insensitive. I kept (?1) in replaceAll method but it didn't work.

package com.test.java;

public class RemoveWords {

    public static void main(String args[])
    {

        // assign some words to string

        String sample ="what Is the latest news today in Europe? is there any thing special or everything is common.";

            System.out.print(sample.replaceAll("( is | the |in | any )(?i)"," "));
    }
}

输出:

what Is latest news today  Europe? there thing special or everything common.

推荐答案

您需要将(?i) 放在想要的模式部分之前不区分大小写:

You need to place the (?i) before the part of the pattern that you want to make case insensitive:

System.out.print(sample.replaceAll("(?i)\\b(?:is|the|in|any)\\b"," "));
                                    ^^^^

> 查看

我用单词边界( \\ b )替换了要删除的关键字周围的空格.之所以会出现问题，是因为可能有两个关键字一个接一个地被一个空格隔开.

I've replaced spaces around the keywords to be removed with word boundary (\\b). The problem comes because there may be two keywords one after another separated by just one space.

如果仅当关键字被空格包围时才想删除关键字，则可以使用正向前行和后向:

If you want to delete the keywords only if they are surrounded by space, then you can use positive lookahead and lookbehind as:

(?i)(?<= )(is|the|in|any)(?= )

> 查看

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