<?php
$str = "test";
$str1 = strtr($str, 't', 'z'); // zesz
$str2 = strtr($str, 'tt', 'z1');// 1es1
$str3 = strtr($str, 't', '');// test
$str4 = strtr($str, 'ts', '12');// 1e21
$str5 = strtr($str, array("t" => '')); // es
$str6 = strtr($str, array("e" => 'www', "s" => "hhh"));// twwwhhht
