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

go to bug id or search bugs for

Bug #73571 foreach() way slower than while(list($key,$value)=each($arr))
Submitted: 2016-11-21 08:56 UTC Modified: 2016-11-21 09:46 UTC
From: spam2 at rhsoft dot net Assigned:
Status: Not a bug Package: Performance problem
PHP Version: 7.0.13 OS:
Private report: No CVE-ID: None
View Add Comment Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If this is not your bug, you can add a comment by following this link.
If this is your bug, but you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: spam2 at rhsoft dot net
New email:
PHP Version: OS:

 

 [2016-11-21 08:56 UTC] spam2 at rhsoft dot net 
Description:
------------
since you depreacte each() with PHP 7.2 better fix foreach() before

[harry@srv-rhsoft:/downloads]$ php each.php
Extract:  0.031516075134277
While:    0.0004878044128418
For-Each: 0.11238217353821


Test script:
---------------
[harry@srv-rhsoft:/downloads]$ cat each.php
<?php
$loops = 2000;

for($x=1;$x<$loops;$x++)
{
 $arr['key' . $x] = 'Test';
}

echo "Extract:  ";
$start = microtime(true);
for($x=1;$x<$loops;$x++)
{
 extract($arr, EXTR_SKIP);
}
echo microtime(true) - $start . "\n";

echo "While:    ";
$start = microtime(true);
for($x=1;$x<$loops;$x++)
{
 while(list($key,$value)=each($arr))
 {
  ${$key} = $value;
 }
}
echo microtime(true) - $start . "\n";

echo "For-Each: ";
$start = microtime(true);
for($x=1;$x<$loops;$x++)
{
 foreach($arr as $key=>$value)
 {
  ${$key} = $value;
 }
}
echo microtime(true) - $start . "\n";
?>

Patches

Add a Patch

Pull Requests

Add a Pull Request

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2016-11-21 09:19 UTC] requinix@php.net
-Status: Open +Status: Not a bug
 [2016-11-21 09:19 UTC] requinix@php.net 
I'll skip the sarcastic response I had planned and instead point out that you didn't reset($arr). Additionally, using EXTR_SKIP gives extract() an advantage over the other two as it doesn't have to re/create variables on loops $x>1. With those two fixed I get

Extract:  0.73130393028259
While:    10.98973608017
For-Each: 0.69374203681946

So it turns out that foreach is actually the fastest.
 [2016-11-21 09:36 UTC] spam2 at rhsoft dot net 
forget the extract() stuff

reset($arr) is a bit unfair since it's a additional function call
 [2016-11-21 09:46 UTC] requinix@php.net 
Additional, yes, but it is required if you use each() - at least if you do multiple times on the same array.

http://php.net/manual/en/function.each.php
> After each() has executed, the array cursor will be left on the next element of the
> array, or past the last element if it hits the end of the array. You have to use
> reset() if you want to traverse the array again using each.

https://3v4l.org/ncnBZ
(note the behavior changed with PHP 7: http://php.net/migration70.incompatible#migration70.incompatible.foreach.array-pointer)
 
PHP Copyright © 2001-2024 The PHP Group
All rights reserved. 		Last updated: Sat Apr 27 05:01:29 2024 UTC