From: martin dot kober at wu-wien dot ac dot at
Operating system: Linux 2.6
PHP version: 5.2.5
PHP Bug Type: Arrays related
Bug description: array_rand doesn't return keys in random order
Description:
------------
The keys that array_rand returns are uniformly distributed, but their
order is not:
Counting the 0, 1 and 2 of the sample code output, I consistently get some
distribution like this:
Overall count (this is fine):
0 1 2
649 694 657
Count per position (this is wrong):
0 1 2
[0] 500 181 319
[1] 149 513 338
0 is way too often in [0] (same for 1 in [1]), there must be some problem
with the algorithm.
Adding a shuffle() is a workaround, but this is a potential trap for users
depending on an even distribution.
There are some similar bugs in the DB, but they are all very old and seem
to be Windows-related.
Reproduce code:
---------------
for ($i = 1; $i <= 1000; $i++) {
echo implode(" ", array_rand(array(1,2,3), 2)), "<br>\n";
}
--
Edit bug report at http://bugs.php.net/?id=43807&edit=1
--
Try a CVS snapshot (PHP 4.4):
http://bugs.php.net/fix.php?id=43807&r=trysnapshot44
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=43807&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=43807&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=43807&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=43807&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=43807&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=43807&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=43807&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=43807&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=43807&r=support
Expected behavior: http://bugs.php.net/fix.php?id=43807&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=43807&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=43807&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=43807&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=43807&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=43807&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=43807&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=43807&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=43807&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=43807&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=43807&r=mysqlcfg
