preg_replace()
preg_replace() replaces pattern matches with a replacement string. Use $1, $2 or ${1} to reference captured groups.
PHP
Intermediate
4 min read
preg_replace() for String Replacement
Example
<?php
// Remove all whitespace
$clean = preg_replace("/\s+/", " ", $text);
// Format phone number
$formatted = preg_replace("/^(\d{3})(\d{3})(\d{4})$/", "($1) $2-$3", "5551234567");
// "(555) 123-4567"
// Strip HTML tags (simplified)
$plain = preg_replace("/<[^>]+>/", "", $html);
// Replace multiple patterns at once
$result = preg_replace(
["/foo/", "/bar/"],
["baz", "qux"],
"foo and bar"
);
// "baz and qux" Pro Tip
Use $1 or ${1} (not \1) for backreferences in preg_replace() replacement strings.