Removing whitespace from strings in Java

Solution 1:

st.replaceAll("\\s+","") removes all whitespaces and non-visible characters (e.g., tab, \n).

st.replaceAll("\\s+","") and st.replaceAll("\\s","") produce the same result.

The second regex is 20% faster than the first one, but as the number consecutive spaces increases, the first one performs better than the second one.

Assign the value to a variable, if not used directly:

st = st.replaceAll("\\s+","")

Solution 2:

replaceAll("\\s","")

\w = Anything that is a word character

\W = Anything that isn't a word character (including punctuation etc)

\s = Anything that is a space character (including space, tab characters etc)

\S = Anything that isn't a space character (including both letters and numbers, as well as punctuation etc)

(Edit: As pointed out, you need to escape the backslash if you want \s to reach the regex engine, resulting in \\s.)

Solution 3:

The most correct answer to the question is:

String mysz2 = mysz.replaceAll("\\s","");

I just adapted this code from the other answers. I'm posting it because besides being exactly what the question requested, it also demonstrates that the result is returned as a new string, the original string is not modified as some of the answers sort of imply.

(Experienced Java developers might say "of course, you can't actually modify a String", but the target audience for this question may well not know this.)

Solution 4:

How about replaceAll("\\s", ""). Refer here.

Solution 5:

One way to handle String manipulations is StringUtils from Apache commons.

String withoutWhitespace = StringUtils.deleteWhitespace(whitespaces);

You can find it here. commons-lang includes lots more and is well supported.