Greedy Java regex

Question

I understand that ? can be used to make modifiers only match the first occurence and prevent the greediness, but maybe I've misunderstood how it's supposed to work. If the string is:

one two three four four four five six

...and I want to capture three. I've been trying:

^one two (.*)(four)+?.*$

...but this gives me three four four. What am I doing wrong? I've tried ?? and .? and just (four)?, but it's not working.

Please refer to the "Quantifiers" section of the [Stack Overflow Regular Expressions FAQ](http://stackoverflow.com/a/22944075/2736496). Particularly the items regarding greediness and reluctance. — aliteralmind, Apr 13 '14 at 18:51

score 6 · Accepted Answer · answered Apr 13 '14 at 18:50

6

Just do this:

^one two (.*?) four.*$

Or you can use \S which means non whitespace characters,

^one two (\\S+) four.*$

answered Apr 13 '14 at 18:50

Sabuj Hassan

36,940
12
73
83

score 3 · Answer 2 · answered Apr 13 '14 at 18:49

3

If you want to capture three you can simply do:

^one two (\w+) four

answered Apr 13 '14 at 18:49

anubhava

713,503
59
514
593

score 1 · Answer 3 · answered Apr 13 '14 at 18:58

This:

^one two (.*)(four)+?.*$

means match one two and then, as much as possible (.*), until you see a four, repeatedly, followed by arbitrary characters.

Possibly you would be better off with splitting this string on white space and inspecting the words ("one",...).

Greedy Java regex

3 Answers3