Regex to find string within square brackets

Question

I need to create three regular expressions to extract the multiple words within square brackets , using the preg_match_all ()

example

Input string:

Lorem [ipsum] dolor sit [[amet]], nam you dolores detracto definitionem. Et admodum fabellas patrioque here, offendit an obstinate sea, vis at [[summo]] alienum cotidieque. Quo tollit dolores cu viderer [Theophrastus] to vix. Cum homes erroribus to assueverit, putant vocent democritum eum ut ipsum nec timeam and Persius. Putant suscipit abhorreant jus cu. Pri doctus feugiat facilisis not. [[[East]]] in sint malis, and Equidem harassment inciderint sea, [[[vocibus]]] id mentitum sea.

1 . desired output for single brackets

[0 ] => Array
        (
           [0 ] => ipsum
           [1 ] => Theophrastus
       )

2 . desired output for double square brackets

[0 ] => Array
       (
           [0 ] => amet
           [1 ] => summo
       )

3 . desired output for triple square brackets

[0 ] => Array
       (
           [0 ] = > East
           [1 ] => vocibus
       )

Appreciate any help !

Do your double & triple `[[` actually have whitespace between them? like `[ [ amet ]]` ? — Michael Berkowski, Apr 09 '14 at 15:02
@MichaelBerkowski there is no whitespace like these [ [ amet ]] just a write error. — z3ne, Apr 09 '14 at 16:27

Eun · Answer 1 · 2014-04-09T15:09:36.150

1

Try following:

preg_match_all("/\[(\s*[\w]*\s*)\]/", $input, $output, PREG_PATTERN_ORDER);

Demo

edited Apr 09 '14 at 15:09

answered Apr 09 '14 at 15:02

Eun

3,993
3
27
47

2

This doesn't produce the output OP wants: "*I need to create three regular expressions to extract the multiple words within square brackets*" – Amal Murali Apr 09 '14 at 15:10

zavalit · Answer 2 · 2014-04-09T16:41:11.957

1

UPDATE:

for 1

preg_match_all('/[^\[]\[([^\[].*)\]/U', $text, $matches)

for 2

preg_match_all('/[^\[]\[\s?\[([^\[].*)\]/U', $text, $matches)

for 3

preg_match_all('/[^\[]\[{3}([^\[].*)\]/U', $text, $matches)

demo

edited Apr 09 '14 at 16:41

answered Apr 09 '14 at 15:25

zavalit

222
2
12

1

This doesn't produce the output the OP wants (particularly the second one and third; the results contain the brackets; see [demo](https://eval.in/134472)). – Amal Murali Apr 09 '14 at 15:40
you are right, i have willingly delete whitespaces betweeen **[ [**, did you really mentioned them? – zavalit Apr 09 '14 at 15:58
What? Did you take a look at the demo? – Amal Murali Apr 09 '14 at 16:00
take it easy man, i really just try to help. – zavalit Apr 09 '14 at 16:03

score 0 · Answer 3 · answered Apr 09 '14 at 16:22

This not-so-readable looking regex should work:

$s = 'Lorem [ ipsum ] dolor sit [[ amet ]] , nam you dolores detracto definitionem . Et admodum fabellas patrioque here , offendit an obstinate sea , vis at [[ summo ]] alienum cotidieque . Quo tollit dolores cu viderer [ Theophrastus ] to vix . Cum homes erroribus to assueverit , putant vocent democritum eum ut ipsum nec timeam and Persius . Putant suscipit abhorreant jus cu . Pri doctus feugiat facilisis not. [[[ East ]]] in sint malis , and Equidem harassment inciderint sea , [[[ vocibus ]]] id mentitum sea .';

if (preg_match_all('/(?<!\[)\[(?!\[)([^]]*)\](?!\[)/', $s, $m))  // single [...]
   print_r($m[1]);

if (preg_match_all('/(?<!\[)\[\[(?!\[)([^]]*)\]\](?!\[)/', $s, $m)) // double [[...]]  
   print_r($m[1]);

if (preg_match_all('/(?<!\[)\[\[\[(?!\[)([^]]*)\]\]\](?!\[)/', $s, $m)) // triple [[[...]]]
   print_r($m[1]);

OUTPUT:

Array
(
    [0] =>  ipsum
    [1] =>  Theophrastus
)
Array
(
    [0] =>  amet
    [1] =>  summo
)
Array
(
    [0] =>  East
    [1] =>  vocibus
)

Regex to find string within square brackets

3 Answers3

OUTPUT: