Grab word after the match with regex

Question

I am trying to get the word with the following:

$string = 'code 10OFF75 +EXTRA';
$regex  = '/(?<=code)\s\w+/';

Output (tried at rubular.com):

10OFF75

I want to skip the special character with the word code. Say, I have the string code: | code- | code:- then how do I grab the next word?

score 3 · Accepted Answer · answered Jun 14 '14 at 05:56

3

You can try to use the \K feature that removes all on the left from match result:

/code\W+\K\w+/

answered Jun 14 '14 at 05:56

Oh surprisingly awesome, can you suggest some resources to learn more about the power of regex. – jogesh_pi Jun 14 '14 at 05:58
@jogesh_pi: You can take a look at this post: http://stackoverflow.com/questions/22937618/reference-what-does-this-regex-mean , you can find informations in the PHP manual, http://pcre.org/pcre.txt , http://rexegg.com , http://regular-expressions.info – Casimir et Hippolyte Jun 14 '14 at 06:00
Nice, +1. Added variations for the day he ends up in C# or JS. :) – zx81 Jun 14 '14 at 06:06
+1 never heard of `\K`. Sadly it only works with PCRE :s – Thank you Jun 14 '14 at 06:16
@naomik: You can use it with Ruby2 too. – Casimir et Hippolyte Jun 14 '14 at 06:21
`grep -P` supports `\K` too, last I checked. – Amal Murali Jun 14 '14 at 06:26

score 2 · Answer 2 · edited May 23 '17 at 11:49

2

What Casimir said (recommended for PCRE)... and other options for the road, in case you find yourself other languages that don't have \K support some day:

With lookbehind

(?<=code\W+)\w+

This will work in .NET and Python's regex module, which have infinite-width lookbehind.

With capturing groups

code\W+(\w+)

The parentheses capture the match to group 1. This works in JavaScript (which doesn't support lookbehind) and most other Perl-style engines.

edited May 23 '17 at 11:49

Community

answered Jun 14 '14 at 06:04

zx81

`(?<=...)` is a positive lookbehind, `(? – Thank you Jun 14 '14 at 06:18
Coincidentally, JavaScript's regexp flavor supports neither `\K` nor lookbehinds **^.^** – Thank you Jun 14 '14 at 06:19
@naomik: yes, the most portable way is the capture group. – Casimir et Hippolyte Jun 14 '14 at 06:27
@AvinashRaj Er... negative-negative lookbehind. :) Thanks for spotting the typo! – zx81 Jun 14 '14 at 06:39

2 Answers2