note 91437 deleted from function.max by danbrown
| From: | danbrown@php.net | Date: | Wed, 10 Jun 2009 12:38:53 +0000 |
| Subject: | note 91437 deleted from function.max by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-156735@lists.php.net to get a copy of this message | ||
Note Submitter: Alexander=dot=Bouz=at=gmx=dot=at
----
sumeruter stated that max() would return the subarray containing the highest value.
http://php.net/manual/en/function.max.php#87547
This is not correct. The decision of max() is made according to the *first* element within the first
nested array.
An example, borrowed from sumeruter:
<?php
$depth3=array(
array(array(1,6,3),array(7,2,5),array(9,3,0)),
array(array(2,1,8),array(4,4,5),array( 99 ,6,7)),
array(array(0,3,2),array(5,91,11),array(42,25,12)));
// it is indeed 99
echo max(max(max($depth3)));
?>
The same example, slightly modified:
<?php
// I just switched the first value of the nested arrays
$depth3=array(
array(array(2,6,3),array(7,2,5),array(9,3,0)),
array(array(1,1,8),array(4,4,5),array( 99 ,6,7)),
array(array(0,3,2),array(5,91,11),array(42,25,12)));
// Whoops, this echoes 9
echo max(max(max($depth3)));
?>
This is because in the first nested max(), the function decides that 2 > 1 > 0 and returns the
array array(array(2,6,3),array(7,2,5),array(9,3,0)) which doesn't contain our highest value.
For this purpose, better use array_walk_recursive().
http://php.net/manual/en/function.array-walk-recursive.php