Question

i have a little problem about preg_match_all and str_replace

<?
    $source = 'hello @user_name, hello @user_name2, hello @user_name3';
    preg_match_all("/@[\w\d_]*/s", $source, $search);
    foreach($search[0] as $result) {
        $source = str_replace($result, "<b>okay</b>", $source);
    }

    echo $source;
?>

the result is (wrong):

hello <b>okay</b>, hello <b>okay</b>2, hello <b>okay</b>3

the right result should be like this:

hello <b>okay</b>, hello <b>okay</b>, hello <b>okay</b>

anyone can help?
Thanks!

Answer 1

It’s happening because the first match, @user_name, will also match @user_name2 and @user_name3 (at least the @user_name part). The way you’ve written it, it’s working as it’s supposed to. You might want to look at preg_replace(). To test regex patterns, I always use My Regex Tester (which isn’t actually mine, that’s just the name of it). Here’s output from that site, complete with code generated:

Raw Match Pattern:
@[\w\d_]*

Raw Replace Pattern:
okay

PHP Code Example: 
<?php
$sourcestring="hello @user_name, hello @user_name2, hello @user_name3";
echo preg_replace('/@[\w\d_]*/s','<b>okay</b>',$sourcestring);
?>

$sourcestring after replacement:
hello <b>okay</b>, hello <b>okay</b>, hello <b>okay</b>