Comments in Regex in PHP
The modifier x allows placing
arbitrary spaces and line breaks
in the regex. Moreover, the hash symbol becomes
a single-line comment symbol (accordingly,
the delimiters will have to be replaced with others).
Let's look at an example. Suppose we have the following regex:
<?php
preg_replace('#[a-z]+@[0-9]+#', '!', 'aaa@333');
?>
Let's use the modifier x and
add explanatory comments for each part
of our regex:
<?php
preg_replace('~
[a-z]+ # letters
@ # at symbol
[0-9]+ # digits
~x', '!', 'aaa@333');
?>
