- similar_text: documentation ( source)
<?php
$var_1 = 'PHP IS GREAT';
$var_2 = 'WITH MYSQL';
similar_text($var_1, $var_2, $percent);
echo $percent;
// 27.272727272727
similar_text($var_2, $var_1, $percent);
echo $percent;
// 18.181818181818