CODEWITHSUNDEEP
javaregexescapingbackslash
Jimmy
Jimmy

Reputation: 189

REGEX Matcher not replacing backslah

The function appendReplacement(StringBuffer sb, String replacement) in Matcher is ignoring escape characters with double backslash. I want to replace two lines into one line separated by \N as it is. Here's my code: 

import java.util.regex.Matcher;
import java.util.regex.Pattern;



public class Test {

    public static void main(String[] args) {
        String str = "Lorem ipsum dolor sit amet,\n"
                + "consectetur adipiscing elit\n"
                + "\n"
                + "sed do eiusmod tempor incididunt ut\n"
                + "labore et dolore magna aliqua\n";
        StringBuffer sb = new StringBuffer();
        Pattern p = Pattern.compile("(.+)\n(.+)\n");
        Matcher m = p.matcher(str);
        while(m.find()) {
            String xyz = m.group(1) + "\\N" + m.group(2);
            System.out.println(xyz);
            m.appendReplacement(sb, xyz);
        }                    
        m.appendTail(sb);
        System.out.println("\n" + sb);
    }

}

OUTPUT:

Lorem ipsum dolor sit amet,\Nconsectetur adipiscing elit sed do eiusmod tempor incididunt ut\Nlabore et dolore magna aliqua

Lorem ipsum dolor sit amet,Nconsectetur adipiscing elit sed do eiusmod tempor incididunt utNlabore et dolore magna aliqua

Upvotes: 1

Views: 176

Answers (1)

thst
thst

Reputation: 4602

Note that backslashes () and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string. Dollar signs may be treated as references to captured subsequences as described above, and backslashes are used to escape literal characters in the replacement string.

You are inserting \N in your xyzString object. The append function will replace backslashed characters with the replacement as if you put it in a String literal. Thus, to get a \N through the append function, you need to escape it twice: \\\\N

Upvotes: 0

Related Questions