Java replaceAll("\\s+") vs replaceAll("\\\\s+")

Question

What's the difference between replaceAll("\\s+") and replaceAll("\\\\s+")? Usually I use \\s+ but sometimes I see \\\\s+.

This should help to solve your problem: http://stackoverflow.com/questions/4653831/regex-how-to-escape-backslashes-and-special-characters — peterremec, Nov 27 '14 at 14:13

score 19 · Accepted Answer · edited Nov 27 '14 at 14:24

19

\\s+ --> replaces 1 or more spaces.

\\\\s+ --> replaces the literal \ followed by s one or more times.

Code:

public static void main(String[] args) {
    String s = "\\sbas  def";
    System.out.println(s);
    System.out.println(s.replaceAll("\\s+", ""));
    System.out.println(s.replaceAll("\\\\s+", ""));

}

O/P :

\sbas  def
\sbasdef
 bas  def

edited Nov 27 '14 at 14:24

khelwood

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answered Nov 27 '14 at 14:14

TheLostMind

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"...followed by s one or more times." Do u mean symbol "s" or spaces? – Maxim Gotovchits Nov 27 '14 at 14:15
But where is the first "\" here "\sbasdef"? – Maxim Gotovchits Nov 27 '14 at 14:18
@MaximGotovchits - the character `s` not spaces. The first `\\` will be escaped. – TheLostMind Nov 27 '14 at 14:18
It also removes control characters like new line, tab, etc. Example: " \r \n\n \t ".replaceAll("\\s+","" ).length() == 0 >> true – Gabe Apr 24 '16 at 19:25

Java replaceAll("\\s+") vs replaceAll("\\\\s+")

1 Answers1