Actually the basic syntax for regular expressions, as supported by preg_replace
and friends, is pretty easy to learn. Think of it as a string describing a pattern with certain characters having special meaning.
In your very simple case, a possible pattern is:
&page-\d+
With \d
meaning a digit (numeric characters 0-9) and +
meaning: Repeat the expression right before +
(here: \d
) one or more times. All other characters just represent themselves.
Therefore, the pattern above matches any of the following strings:
&page-0
&page-665
&page-1234567890
Since the preg
functions use a Perl-compatible syntax and regular expressions are denoted between slashes (/
) in Perl, you have to surround the pattern in slashes:
$after = preg_replace('/&page-\d+/', '', $before);
Actually, you can use other characters as well:
$after = preg_replace('#&page-\d+#', '', $before);
For a full reference of supported syntax, see the PHP manual.