How do I make Java ignore the number of spaces in a string when splitting?

Question

Possible Duplicate:
How do I split a string with any whitespace chars as delimiters?

Both of these Python lines gives me exactly the same list:

print("1 2 3".split())
print("1  2   3".split())

Output:

['1', '2', '3']
['1', '2', '3']

I was surprised when the Java 'equivalents' refused:

System.out.println(Arrays.asList("1 2 3".split(" ")));
System.out.println(Arrays.asList("1  2   3".split(" ")));

Output:

[1, 2, 3]
[1, , 2, , , 3]

How do I make Java ignore the number of spaces?

Arnaud Le Blanc · Accepted Answer · 2011-02-01T11:41:17.173

26

Try this:

"1  2  3".split(" +")

// original code, modified:
System.out.println(Arrays.asList("1 2 3".split(" +")));
System.out.println(Arrays.asList("1  2   3".split(" +")));

The argument passed to split() is a Regex, so you can specify that you allow the separator to be one or more spaces.

I you also allow tabs and other white-space characters as separator, use "\s":

"1  2  3".split("\\s+")

And if you expect to have trailing or heading whitespaces like in " 1 2 3 ", use this:

 "  1 2   3   ".replaceAll("(^\\s+|\\s+$)", "").split("\\s+")

edited Feb 01 '11 at 11:41

answered Feb 01 '11 at 11:14

Arnaud Le Blanc

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Isn't the built-in `String.trim()` faster and a little more readable than `String.replaceAll("(^\\s+|\\s+$)", "")` or am I missing something ? – Costi Ciudatu Feb 01 '11 at 11:52
3

^^ True, but then he wouldn't have the opportunity to show off his 1337 REGEX SKLZ. ;-) – Chris Nava Feb 01 '11 at 15:57
haha :-) I was thinking that trim was only triming the space character – Arnaud Le Blanc Feb 01 '11 at 16:08
Worked flawlessly. I didn't realize that split() didn't consider &*#&ing leading whitespace so thanks for mentioning that issue in particular. – user124384 Sep 24 '15 at 00:31
@arnaud576875 Thank you a lot :) – d3vpasha Apr 28 '16 at 21:10

Uszui · Answer 2 · 2011-02-01T11:39:59.127

4

How about using a neat regular expression? Note that according to Java API documentation, String.split will take a regular expression string parameter.

"1 2   3".split("\\s+")

edited Feb 01 '11 at 11:39

answered Feb 01 '11 at 11:21

Uszui

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score 3 · Answer 3 · answered Feb 01 '11 at 11:23

3

I think this should do:

yourString.trim().split("\\s+");

answered Feb 01 '11 at 11:23

Costi Ciudatu

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score 1 · Answer 4 · answered Feb 01 '11 at 11:23

1

I prefer "1 2 3".split("\s+") than "1 2 3".split(" +"). When you use \s instead of " " it is more readable and safer.

answered Feb 01 '11 at 11:23

AlexR

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How do I make Java ignore the number of spaces in a string when splitting?

4 Answers4