Edit report at https://bugs.php.net/bug.php?id=63893&edit=1
ID: 63893
Comment by: mariancjc at gmail dot com
Reported by: scope at planetavent dot de
Summary: poor efficiency of strtr() using array with keys of
very different length
Status: Closed
Type: Bug
Package: Strings related
Operating System: Windows Server 2008 / RHEL 6.3
PHP Version: 5.4.10
Assigned To: cataphract
Block user comment: N
Private report: N
New Comment:
With the release of 5.4.12 strtr() now triggers a Notice (Notice: Array to
string conversion in
...) if one of the array elements is an array (using the two arguments
variant), even if the key
is not used/found in the string (first argument)
so this:
<?php echo strtr('aa, bb', array(
'aa'=>'qqq',
'bb'=>'www',
'cc'=>array('what', 'ever')
) );
Before 5.4.12 strtr() triggered the notice only if the key was found in the
string
I don't know if this is as intended, but breaks existing application behavior
(Kohana 3.3)
Regards
Previous Comments:
------------------------------------------------------------------------
[2013-01-15 20:52:05] [email protected]
The fix for this bug has been committed.
Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
For Windows:
http://windows.php.net/snapshots/
Thank you for the report, and for helping us make PHP better.
Fixed in 5.4 and up.
------------------------------------------------------------------------
[2013-01-07 02:17:25] [email protected]
My patch so far:
https://github.com/cataphract/php-src/compare/strtr
------------------------------------------------------------------------
[2013-01-03 14:34:36] scope at planetavent dot de
Description:
------------
As the documentation of strtr() points out, strtr "... will be the most
efficient when all the keys have the same size".
Using keys of very different lengths results in poor performance, even on very
small inputs.
If the str_repeat() for "m" in the test script is adjusted to 20000 the
resulting runtime increases to 45 seconds for strtr() while str_replace() does
not increase notably.
There are cases where the replacement array is built dynamically, so there
might be little control over the keylengths. It's easy to expand the example
such that strtr() takes several hours compared to just a few seconds using
str_replace().
Test script:
---------------
<?php
$text = str_repeat( 'm', 2000 );
$long_from_a = str_repeat( 'a', 1 );
$long_from_x = str_repeat( 'x', 1500 );
$replacements = array(
$long_from_a => 'b',
$long_from_x => 'y'
);
$start = microtime( true );
$result_1 = strtr( $text, $replacements );
echo "strtr: " . number_format( microtime( true ) - $start, 4 ) . "\n";
$start = microtime( true );
$result_2 = str_replace( array_keys( $replacements ), array_values(
$replacements ), $text );
echo "str_replace: " . number_format( microtime( true ) - $start, 4 ) . "\n";
echo $result_1 === $result_2 ? "results match!\n": "no match!\n";
Expected result:
----------------
strtr: 0.0001
str_replace: 0.0001
results match!
Actual result:
--------------
strtr: 2.4203
str_replace: 0.0001
results match!
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=63893&edit=1
