[PHP] Weird Behaviour of Array

[Ruwan Pathmalal]

Hi People,
I confused with weird behaviour of array. Following is my script.

<?php
$array = array(
            '12_1'=>array(
                    56=>array(
                            23=>'23',
                            33=>'33')
                    ),
        '12_5'=>array(
                    55=>'55'
            )
        );

$array['12_5'][55][45] = '45';
$array['12_5'][55][56] = '76';
$array['12_5'][55][85] = '85';
$array['12_5'][55][96] = '96';
print_r($array);
?>

Output is -:
Array ( [12_1] => Array ( [56] => Array ( [23] => 23 [33] => 33 ) ) [12_5]
=> Array ( [55] => 55 4 7 8 9 ) )

Sometime this is because, first time $array['12_5'][55] not an array. I
assigned value to it like array. (I suppose overwrite key and then assign
given value as key value pair). See this part of output [12_5] => Array (
[55] => 55 4 7 8 9 ). It compose 4 from 45, 7 from 76, 8 from 85 like that
(first digit of assigned values).

I manage to overcome this problem by unsettling  $array['12_5'][55] before
assigning value to it.

But I want to know why this happening or is this PHP bug ? (Clear
explanation for situation :) )

Thanks
Ruwan