Question

 $search  = array('A', 'B', 'C', 'D', 'E');
 $replace = array('B', 'C', 'D', 'E', 'F');
 $subject = 'A';
 $trans = array('A' => 'B','B'=>'C','C'=>'D','D'=>'E','E'=>'F');
 echo str_replace($search, $replace, $subject);
 echo "<br/>";
 echo strtr($subject,$trans);

 Output: F
         B

When using str_replace I get F, using strtr i get B

As far I am getting this, for str_replace: It replaces from left to right, so A gets replaced with B without marking the position was already replaced, so again finds B which is replaced by C and so on to get value F.

For strtr: I replaces A with B and remembers it has replaced at that position,

Am i getting this correctly? could someone explain to me?

Answer 1

Yes, that is correct. str_replace() does its replacements sequentially, whereas strtr() works through each character in the string and replaces it only once.