[SOLVED] str_replace help!!!!

[serbestgezer]

I am trying to replace second character in the string with x when I use str_replace it replace it all "a" with x. Is there any way to replace

second character in the string?

<?php
$subject = "baaia";

$body = str_replace($subject[2], "x", $subject);

echo $body;
// bxxix

I want to print like "bxaia"

?>

 

[Garethp]

$body = preg_replace('~(.).(.*)~s', "$1x$2", $subject);

[serbestgezer]

thanks mate