Edit report at https://bugs.php.net/bug.php?id=53724&edit=1
ID: 53724
Updated by: cmb@php.net
Reported by: lukas dot starecek at centrum dot cz
Summary: array_diff like methods compares false as identity
and true as equal
-Status: Open
+Status: Not a bug
Type: Bug
Package: Arrays related
Operating System: Irrelevant
PHP Version: 5.3.5
-Assigned To:
+Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
As tbrasta has already explained, this is not a bug. I agree, though, that the documentation of
array_diff() should be improved, by linking to array_diff_uassoc(), array_udiff_assoc() and
array_udiff_uassoc() in the "see also" section. I've submitted a respective patch via
the online editor.
Previous Comments:
------------------------------------------------------------------------
[2011-02-21 23:23:25] lukas dot starecek at centrum dot cz
Ah I did not noticed this "grey" part of method documentation in examples. You are right,
documentation says it, but imho in not so clear way. I have read only specifications, not examples.
Imho documentation could be a little bit more exact, because this is important.
So sadly this functions are designed only for string comparison, not for general variable comparison
:-/ .
My fault, bogus, sorry. But think about functions of this kind for general variables comparison, not
only for string comparison :-) .
------------------------------------------------------------------------
[2011-02-20 16:20:18] tbrasta at gmail dot com
This is not a bug. The function is operating exactly as stated in the documentation, i.e. casted to
string values are compared. Since (string) 0 = "0", (string) false = "" and
(string) "0" = "0" but "0" !== "", you get the result as it
should be.
------------------------------------------------------------------------
[2011-01-12 14:27:34] lukas dot starecek at centrum dot cz
A little mistake, '' behaves as same with false, so problem is only in comparing 0 and
'0' (and maybee some other variables I did not used).
------------------------------------------------------------------------
[2011-01-12 14:16:39] lukas dot starecek at centrum dot cz
Description:
------------
array_diff functions compares boolean false as identity (operator "===") and boolean true
as equal (operator "==") so behaves inconsistently. It should compare all values in same
way and in my opinion it should compare as equals ("==") or have argument (or another
mechanism) how to set whether compare by equal or identity.
As example I use array_diff_assoc but I think it will probably behave simmilary with another array
realted functions (array_diff%, array_intersect%). In expected result I suppose comparing as equal
(operator '==').
In example you can see, that array_diff_assoc behaves in such way that 0 or '0' or
'' is not same as false, but 1 or '1' is same as true. So false is compared like
'===' and true is compared like '=='. Because 0 is same as '0' and 1
is same as '1' I suppose, that this problem is only for boolean false value.
Test script:
---------------
$arr1 = array('a' => 0, 'b' => 1, 'c' =>
'0', 'd' => '1', 'e' => '',
'f' => false, 'g' => true, 'h' => 0, 'i' =>
1);
$arr2 = array('a' => false, 'b' => true, 'c' => false,
'd' => true, 'e' => false, 'f' => false, 'g' =>
true, 'h' => '0', 'i' => '1');
var_dump(array_diff_assoc($arr1, $arr2));
Expected result:
----------------
array(0) {
}
Actual result:
--------------
array(2) {
["a"]=>
int(0)
["c"]=>
string(1) "0"
}
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=53724&edit=1