regex - how to compare two strings of same contents but different in order in php -

i want compare 2 strings having same number of words , same contents opposite in sequence.

str1 = first day of spring  str2 = day of first spring 

or

str2 = day first spring of  

the above strings same in contents different in order. answer true in these situations otherwise false.

first split both strings explode() in array posisble difference.

<?php  $str1 = 'first day of spring'; $str2 = 'day of first spring';  $array1 = explode(" ", $str1); $array2 = explode(" ", $str2);  $fulldiff = array_merge(array_diff($array1, $array2), array_diff($array2, $array1));  if($fulldiff > 0){     echo 'false'; }else{     echo 'true'; } ?>