How to replace multiple values in php -

$srting = "test1 test1 test2 test2 test2 test1 test1 test2"; 

how can change test1 values test2 , test2 values test1 ?
when use str_replace , preg_replace values changed last array value. example:

$pat = array(); $pat[0] = "/test1/"; $pat[1] = "/test2/"; $rep = array(); $rep[0] = "test2"; $rep[1] = "test1"; $replace = preg_replace($pat,$rep,$srting) ; 

result:

test1 test1 test1 test1 test1 test1 test1 test1  

this should work you:

<?php      $string = "test1 test1 test2 test2 test2 test1 test1 test2";      echo $string . "<br />";     echo $string = strtr($string, array("test1" => "test2", "test2" => "test1"));  ?> 

output:

test1 test1 test2 test2 test2 test1 test1 test2 test2 test2 test1 test1 test1 test2 test2 test1 

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