Be careful when replacing characters (or repeated patterns in the FROM and TO arrays):
For example:
<?php
$arrFrom = array("1","2","3","B");
$arrTo = array("A","B","C","D");
$word = "ZBB2";
echo str_replace($arrFrom, $arrTo, $word);
?>
I would expect as result: "ZDDB"
However, this return: "ZDDD"
(Because B = D according to our array)
To make this work, use "strtr" instead:
<?php
$arr = array("1" => "A","2" => "B","3" => "C","B" => "D");
$word = "ZBB2";
echo strtr($word,$arr);
?>
This returns: "ZDDB"