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Answer 1

+17 A:

String a = "Some    text  with   spaces";
String b = a.replaceAll("\\s+", " ");
assert b.equals("Some text with spaces");

Tim Jansen 2009-02-22 19:21:40

This will make replacements of all single spaces with a single space, not very efficient. You should only replace if there are two or more consecutively.

Chris Ballance 2009-02-22 20:43:22

@Chris - don't start optimizing the regex prematurely, I believe this will suffice.

Yuval A 2009-02-22 21:23:10

Yes, this solution is not as efficient as it could be, but that would only matter if this operation were taking place inside a performance hotspot. It's definitely not worth a downvote.

Alan Moore 2009-02-22 21:31:08

There's nothing optimized about not replacing single spaces with single spaces. This *guarantees* a string replacement for every word boundary in your string.

Chris Ballance 2009-02-22 23:34:35

It's a valid point, and I would always use \s{2,} or equivalent in this situation, but practically speaking, it's just not that important.

Alan Moore 2009-02-23 03:03:38

I wouldn't be surprised if this is optimized by the libraries already to only do replacements on multiple spaces. This is readable and gets the job done.

Rontologist 2009-02-23 22:30:01

Answer 2

+4 A:

If we're talking specifically about spaces, you want to be testing specifically for spaces:

MyString = MyString.replaceAll(" +", " ");

Using \s will result in all whitespace being replaced - sometimes desired, othertimes not.

Also, a simpler way to only match 2 or more is:

MyString = MyString.replaceAll(" {2,}", " ");

(Of course, both of these examples can use \s if any whitespace is desired to be replaced with a single space.)

Peter Boughton 2009-02-22 21:07:49

It worth remembering that you need something like myString = myString.replaceAll(" +", " "); otherwise it won't do anything useful.

Peter Lawrey 2009-02-23 20:27:15

Indeed - I think I simply copied the format of a (now deleted) answer, but will correct it.

Peter Boughton 2009-02-23 22:14:18

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Java Regex - reduce spaces in a string

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