Java replace all square brackets in a string

Question

I want to remove square brackets from a string, but I don't know how.

String str = "[Chrissman-@1]";
str = replaceAll("\\[\\]", "");

String[] temp = str.split("-@");
System.out.println("Nickname: " + temp[0] + " | Power: " + temp[1]);

But my result is: [Chrissman | 1] The square brackets doesn't get removed.

I tried using a different regex: "\\[.*?\\]", "\\[\\d+\\]" but the result is the same, the square brackets still attached on the string.

Edit:

I tried:

str.replaceAll("]", "");
str.replaceAll("[", "");

And now I'm getting:

Exception in thread "Thread-4" java.util.regex.PatternSyntaxException: Unclosed character class near index 0
[
^
    at java.util.regex.Pattern.error(Unknown Source)
    at java.util.regex.Pattern.clazz(Unknown Source)
    at java.util.regex.Pattern.sequence(Unknown Source)
    at java.util.regex.Pattern.expr(Unknown Source)
    at java.util.regex.Pattern.compile(Unknown Source)
    at java.util.regex.Pattern.<init>(Unknown Source)
    at java.util.regex.Pattern.compile(Unknown Source)
    at java.lang.String.replaceAll(Unknown Source)

Answer 1

The replaceAll method is attempting to match the String literal [] which does not exist within the String try replacing these items separately.

String str = "[Chrissman-@1]";
str = str.replaceAll("\\[", "").replaceAll("\\]","");

Answer 2

Your regex matches (and removes) only subsequent square brackets. Use this instead:

str = str.replaceAll("\\[|\\]", "");

If you only want to replace bracket pairs with content in between, you could use this:

str = str.replaceAll("\\[(.*?)\\]", "$1");

Answer 3

You're currently trying to remove the exact string [] - two square brackets with nothing between them. Instead, you want to remove all [ and separately remove all ].

Personally I would avoid using replaceAll here as it introduces more confusion due to the regex part - I'd use:

String replaced = original.replace("[", "").replace("]", "");

Only use the methods which take regular expressions if you really want to do full pattern matching. When you just want to replace all occurrences of a fixed string, replace is simpler to read and understand.

(There are alternative approaches which use the regular expression form and really match patterns, but I think the above code is significantly simpler.)

Answer 4

use regex [\\[\\]] -

String str = "[Chrissman-@1]";
String[] temp = str.replaceAll("[\\[\\]]", "").split("-@");
System.out.println("Nickname: " + temp[0] + " | Power: " + temp[1]);

output -

Nickname: Chrissman | Power: 1

Answer 5

You may also do it like this:

String data = "[yourdata]";
String regex = "\\[|\\]";
data  = data .replaceAll(regex, "");
System.out.println(data);

Answer 6

I use this regex to replace every string inside brackets:

var= var.replaceAll("\\[\\w+", "[*").replaceAll("\\]", "]");