php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #75172 $replace_pairs can't be used instead of $to and $from
Submitted: 2017-09-08 10:25 UTC Modified: 2017-09-08 10:33 UTC
From: hyman dot omg at gmail dot com Assigned:
Status: Not a bug Package: Strings related
PHP Version: 5.6.31 OS: centos6.5
Private report: No CVE-ID: None
View Developer Edit
 [2017-09-08 10:25 UTC] hyman dot omg at gmail dot com 
Description:
------------
In PHP Manual,we can find the message "The replace_pairs parameter may be used instead of to and from, in which case it's an array in the form array('from' => 'to', ...)".In fast,the results are different,it doesn't work as documented.

Test script:
---------------
<?php
    $str = 'I loved you';
    $from = 'love';
    $to = 'lOvE';
    var_dump($result1 = strtr($str, $from, $to));//I lOvEd yOu
    var_dump($result2 = strtr($str, [$from=>$to]));//I lOvEd you
    var_dump($result1===$result2);//false

Expected result:
----------------
I lOvEd you
I lOvEd you
true

Actual result:
--------------
I lOvEd yOu
I lOvEd you
false

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2017-09-08 10:33 UTC] requinix@php.net
-Status: Open +Status: Not a bug
 [2017-09-08 10:33 UTC] requinix@php.net 
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

Please read all the docs, not just parts of it.

> If given three arguments, this function returns a copy of str where all
> occurrences of each (single-byte) character in from have been translated to the
> corresponding character in to

> If given two arguments, the second should be an array in the form array('from'
> => 'to', ...). The return value is a string where all the occurrences of the
> array keys have been replaced by the corresponding values.

That is, strtr has two different behaviors: character replacement by passing two strings or string replacement by passing one array.
 [2017-09-08 10:33 UTC] kelunik@php.net 
These are replace pairs, see https://3v4l.org/3rfuV

<?php

$str = 'I loved you';
$from = 'love';
$to = 'lOvE';

var_dump($result1 = strtr($str, $from, $to));
var_dump($result2 = strtr($str, [$from[0] => $to[0], $from[1] => $to[1], $from[2] => $to[2], $from[3] => $to[3]]));
var_dump($result2 = strtr($str, [$from => $to]));
var_dump($result1===$result2);//false
 [2017-09-08 10:33 UTC] mail at pmmaga dot net 
You are misreading the docs. It states:

> If given three arguments, this function returns a copy of str where all occurrences of each (single-byte) character in from have been translated to the corresponding character in to.

It says, "of each character". So all your lowercase "o" and "e" will be uppercased in your example.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Sun May 18 08:01:27 2025 UTC