Capture matched values in regex

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I use this regex \\wx\\w\\w\\w\\w to split a string. I'm attempting to match 0x0441,a,2,3,4 and 0x0442,f,dws,212 from the following string : "0x0441,a,2,3,4,0x0442,f,dws,212"

Using the regex with code below :

import java.io.IOException;
import java.util.Arrays;

public class ReadLine {

    public static void main(String args[]) throws IOException {

        final String str = "0x0441,a,2,3,4,0x0442,f,dws,212";

        Arrays.stream(str.split("\\wx\\w\\w\\w\\w")).forEach(split -> System.out.println(split));

    }
}

prints :

,a,2,3,4,
,f,dws,212

I expect the output to be :

0x0441,a,2,3,4,
0x0442,f,dws,212

How to also capture the matched values 0x0441 & 0x0442 ?

regex java
1 Answers

Use a positive lookahead:

Arrays.stream(str.split("(?=\\wx\\w\\w\\w\\w)"))
    .forEach(System.out::println);

Demo

Note that your regular expression can be written more simply with a quantifier (as mentioned by Arvind Kumar Avinash).

Arrays.stream(str.split("(?=\\wx\\w{4})"))
    .forEach(System.out::println);
user_95131840
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