Hemaulo Hemaulo - 26 days ago 8
PHP Question

Regex for matching CSS hex colors

I'm trying to write regex that extracts all hex colors from CSS code.

This is what I have now:

Code:

$css = <<<CSS

/* Do not match me: #abcdefgh; I am longer than needed. */

.foo
{
color: #cccaaa; background-color:#ababab;
}

#bar
{
background-color:#123456
}
CSS;

preg_match_all('/#(?:[0-9a-fA-F]{6})/', $css, $matches);


Output:

Array
(
[0] => Array
(
[0] => #abcdef
[1] => #cccaaa
[2] => #ababab
[3] => #123456
)

)


I don't know how to specify that only those colors are matched which ends with punctuation, whitespace or newline.

Answer

Since a hex color code may also consist of 3 characters, you can define a mandatory group and an optional group of letters and digits, so the long and elaborate notation would be:

/#([a-f]|[A-F]|[0-9]){3}(([a-f]|[A-F]|[0-9]){3})?\b/

Or if you want a nice and short version, you can say that you want either 1 or 2 groups of 3 alphanumeric characters, and that they should be matched case insensitively (/i).

/#([a-f0-9]{3}){1,2}\b/i