nikolaz dot tang at hotmail dot com's solution of using json_encode/decode is interesting, but a couple of issues to be aware of with it.

<?php
// From: nikolaz dot tang at hotmail dot com's post
function str_replace_json($search, $replace, $subject){
     return json_decode(str_replace($search, $replace,  json_encode($subject)));
}
?> 

json_decode will return objects, where arrays are probably expected.  This is easily remedied by adding 2nd parameter 'true' to json_decode.

$search and $replace could contain strings that match json encoding, which will either change the structure returned by this method, or break the json.

ie:
<?php
var_dump(str_replace_json('":"', '","', ['this' => 'stuff']));
var_dump(str_replace_json('this":"', 'this" : "thing", "with":"', ['this' => 'stuff']));
?>