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

go to bug id or search bugs for

Bug #75310 range(0.94, 0.49, -0.01) difference
Submitted: 2017-10-04 19:43 UTC Modified: 2019-01-28 23:10 UTC
Votes:2
Avg. Score:3.5 ± 0.5
Reproduced:0 of 0 (0.0%)
From: shawn at mckenzies dot net Assigned:
Status: Not a bug Package: Arrays related
PHP Version: 7.0.3 OS: Win,Linux
Private report: No CVE-ID: None
View Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: shawn at mckenzies dot net
New email:
PHP Version: OS:

 

 [2017-10-04 19:43 UTC] shawn at mckenzies dot net 
Description:
------------
range(0.94, 0.49, -0.01) returns a 45 element array from .94 to .5 in PHP 7.0.3 - 7.2.0rc2 but returns the expected 46 element array .94 to .49 in PHP 5.6.0 - 5.6.30.

Test script:
---------------
https://3v4l.org/gZ3cs#v703

$a = range(0.94, 0.49, -0.01);
echo count($a).PHP_EOL;
echo min($a).PHP_EOL;
print_r($a);



Expected result:
----------------
Same array should be created created across PHP versions.

Patches

Pull Requests

Pull requests:

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2017-10-04 19:49 UTC] shawn at mckenzies dot net
-Summary: range(0.94, 0.49, -0.01) difference +Summary: range(0.94, 0.49, -0.01) difference -Operating System: Win7,Linux +Operating System: Win,Linux -PHP Version: 7.2.0RC3 +PHP Version: 7.0.3
 [2017-10-04 19:49 UTC] shawn at mckenzies dot net 
Seems to have been introduced in 7.0.3.
 [2017-10-04 19:55 UTC] requinix@php.net
-Status: Open +Status: Not a bug
 [2017-10-04 19:55 UTC] requinix@php.net 
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://www.floating-point-gui.de/

Thank you for your interest in PHP.

PHP can't really guarantee any particular behavior; pick different pairs of numbers and you'll get different results. https://3v4l.org/JtEG9
 [2017-10-04 22:20 UTC] mail at pmmaga dot net 
I would actually consider this a bug as it is currently inconsistent as you also showed. (Different pairs act as expected)

I have linked a PR for a fix.
 [2017-10-05 04:30 UTC] requinix@php.net
-Status: Not a bug +Status: Re-Opened
 [2017-10-05 04:30 UTC] requinix@php.net 
Fair enough.
 [2019-01-28 23:10 UTC] pmmaga@php.net
-Status: Re-Opened +Status: Not a bug
 [2019-01-28 23:10 UTC] pmmaga@php.net 
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://www.floating-point-gui.de/

Thank you for your interest in PHP.

Although I had provided a possible fix, it would be incomplete (it would still fail for very small numbers). Given that, I'm closing this.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Wed Jul 02 07:01:33 2025 UTC