replaceAll not working as expected on a String

Question

I have this line of code: temp5.replaceAll("\\W", "");

The contents of temp5 at this point are: [1, 2, 3, 4] but the regex doesn't remove anything. And when I do a toCharArray() I end up with this: [[, 1, ,, , 2, ,, , 3, ,, , 4, ]]

Am I not using the regex correctly? I was under the impression that \W should remove all punctuation and white space.

Note: temp5 is a String

And I just tested using \w, \W, and various others. Same output for all of them

• north.mister: yes temp 5 is a string

Answer 1

Strings are immutable. replaceAll() returns the string with the changes made, it does not modify temp5. So you might do something like this instead:

temp5 = temp5.replaceAll("\\W", "");

After that, temp5 will be "1234".

• north.mister: Oh my god....I am stupid....thanks a bunch (should have read the freaking API ugh)
• Amit Joki: looks like 2day, you will reach 10K :)

Answer 2

 String temp5="1, 2, 3, 4";
 temp5=temp5.replaceAll("\\W", "");
 System.out.println(temp5.toCharArray());

This will help