Use php preg_match_all() to capture uuids followed by # character - php

Question

how to use preg_match_all() to get 1a1a-1a1a and 2B2B2-B2in the following string :
$string = 'Hello #1a1a-1a1a and #2B2B2-B2 too';
my aim is to capture every # followed by a uuid.
i tried :
preg_match_all("/#(.*)/", $string, $matches);
preg_match_all("/#.*?/U", $string, $matches);
preg_match_all("/#([^\"]+)/si", $a, $matches);
but can't make it

Answer 1

Use /(?<=#)[\w-]+/ pattern that match any string after #
preg_match_all("/(?<=#)[\w-]+/", $string, $matches);
print_r($matches[0]);
Output
Array
(
[0] => 1a1a-1a1a
[1] => 2B2B2-B2
)
Check result in demo

Answer 2

The #(.*) regex matches a # and the greedily any 0 or more chars other than line break chars (i.e. the rest of the line). /#.*?/U is a synonymous pattern, it is equal to /#.*/, the text after # just is not captured into a group. #([^\"]+) matches # and captures into Group 1 any one or more chars other than " and that will either match up to the first " or end of string if there is no ".
I suggest using
preg_match_all('~#\K[\w-]+~', $s, $matches)
See the regex demo. #\K[\w-]+ will match # and \K will remove it from the match, and [\w-]+ will match 1 or more word or - chars that will be returned.
To make the pattern a bit more restrictive, say, to only match letters or digits after # that can be hyphen separated, you may use
'~#\K[A-Z0-9]+(?:-[A-Z0-9]+)*~i'
See this regex demo. Here, [A-Z0-9]+ matches 1 or more alphanumeric chars and (?:-[A-Z0-9]+)* will match 0 or more repetitions of a - followed with 1+ alphanumeric chars. i modifier will make the pattern case insensitive.

Answer 3

Your regexes ar matching:
#(.*) Matches # and captures in a group any character 0+ times greedy including the space which will match all in your example
#.*? Matches # followed by any character 0+ times non greedy which will only match the #
#([^\"]+) Matches # and captures in a group matching not a " which will match all in your example
To capture every # followed by a uuid, you could use a character class to list what you would allow to match and repeat that pattern preceded by a dash in a non capturing group 1+ times.
If you want to match the uuid only, you could capture the values in a capturing group.
#([a-zA-Z0-9]+(?:-[a-zA-Z0-9]+)+)
Regex demo
$string = 'Hello #1a1a-1a1a and #2B2B2-B2 too';
preg_match_all("/#([a-zA-Z0-9]+(?:-[a-zA-Z0-9]+)+)/", $string, $matches);
print_r($matches[1]);
Result
Array
(
[0] => 1a1a-1a1a
[1] => 2B2B2-B2
)
Demo php

Answer 4

Try this, it will catch everything after '#', no matter how many characters
preg_match_all("#(\w)*/", $string, $matches)