Question

I have a string which contains a case id.

Example strings:

[Case 123]
lorem[Case 123]ipsum
[Case 123]ipsum

I want to get the id (123) from the string.

I tried (on string [Case 1359] needsmoreinfo):

$pattern = '/[Case (\d+)]/';
preg_match($pattern, $message->subject, $matches, PREG_OFFSET_CAPTURE);

Which resulted in:

o[0][0]: C
    [1]: 1

Not really what I was looking for 🙂

What should the pattern look like, or is there another flaw somewhere?

Answer 1

[ and ] are characters with special meaning in regular expressions. You need to escape them to tell the regex engine to search for literal [ and ] characters:

$pattern = '/\[Case (\d+)\]/';
preg_match($pattern, $message->subject, $matches, PREG_OFFSET_CAPTURE);

See more on what these characters do when unescaped: regular expression character classes.