negate regex : not matching a specific word containing numbers-CodePudding

I want to use replace all characters that do not match the word => bac [0-9], if someone can help Edit

I tried :

String test = "bac  5 - and plus";
test = test.replaceAll("^(?!.*bac \\ [0-9]).*","")

===>I want result test = "bac 5"

CodePudding user response：

Use a look behind:

test = test.replaceAll("(?<=bac \\ \\d).*","");

CodePudding user response：

Your pattern with the negative lookahead ^(?!.*bac \ [0-9]).* means to match the whole line if it does not contain this pattern bac \ [0-9]

You can use a capture group instead for the part that you want to keep, and match the rest of the line that should be removed.

In the replacement, use group 1 with $1

String test = "bac  5 - and plus";
test = test.replaceAll("(bac \\ \\d).*","$1");
System.out.println(test);

Output

bac  5