PHP preg_replace regex, get number between parenth

Question

This is driving me nuts! I need a regex to extract a number from a string. The number might include a - (minus) or _ (underscore) sign, preferably using preg_replace.

The example string: "This is 1 example (text) with a (number)(01230_12-3)".

What I need to extract is the (01230_12-3), but without the parenthesis.

So far, this is what I have:

$FolderTitle[$Counter]) = "This is 1 example (text) with a (number)(01230_12-3)";
$FolderNumber[$Counter] = preg_replace("/([^0-9-_])/imsxU", '', $FolderTitle[$Counter]);

Answer 1

• When using preg_match() an output variable is necessary, so I am using a shorthand conditional to determine if there was a match and setting the necessary value to the echo.
• You need to match the leading ( then forget it with \K then match as many of the qualifying characters as possible.
• None of those pattern modifiers were necessary, so I removed them.
• You can replace my echo with your $FolderNumber[$Counter] =
• the leading parenthesis in the pattern must be escaped with \.
• \d is the same as [0-9].

Code: (Demo)

$Counter = 0;
$FolderTitle[$Counter] = "This is 1 example (text) with a (number)(01230_12-3)";
echo preg_match("/\(\K[-\d_]+/", $FolderTitle[$Counter], $out) ? $out[0] : 'no match';

Output:

01230_12-3