PHP array_diff weirdness - php

Question

This is such a simple problem but the PHP doc does not explain why it is happening.
I have this code:
var_dump($newattributes); var_dump($oldattributes);
var_dump(array_diff($newattributes, $oldattributes));
For briefity I am going to omit large parts of the structure I am actually using (since each is 117 elements long) and cut to the case.
I have one array called $newattributes which looks like:
array(117){
// Lots of other attributes here
["deleted"] => int(1)
}
And another called $oldattributes which looks like:
array(117){
// Lots of other attributes here
["deleted"] => string(1) "0"
}
Which looks different right? According to array_diff: no. The output I get from array_diff is:
array(0) { }
I have read the documentation page however it says:
Two elements are considered equal if and only if (string) $elem1 ===
(string) $elem2. In words: when the string representation is the same.
And I am not sure how "1" can object equal "0".
So am I seeing some caveat with array_diff I didn't take into consideration?

Answer 1

The problem might reside in the fact that you are using associative arrays : you should try and use the following for associative arrays : array_diff_assoc():
<?php
$newattributes = array(
"deleted" => 1
);
$oldattributes = array(
"deleted" => "0"
);
$result = array_diff_assoc($newattributes, $oldattributes);
var_dump($result);
?>
result :
array(1) {
["deleted"]=>
int(1)
}

Answer 2

It does happen to me too (when there are more values than one)
$new = array('test' => true, 'bla' => 'test' 'deleted' => 1);
$old = array('test' => true, 'deleted' => '0');
For a full array_diff you need to make some extra work, because in default it returns a relative complement
Try this:
array_diff(array_merge($new, $old), array_intersect($new, $old))
Result:
Array
(
[bla] => test
[deleted] => 0
)