Bug #14805 Updated: array_unique works opposed to the manual

ID: 14805 Updated by: venaas@php.net Reported By: pgerzson@freestart.hu -Status: Assigned +Status: Closed Bug Type: Arrays related Operating System: MS Windows 98 PWS 4.0 PHP Version: 4.1.1 Assigned To: venaas New Comment: I've now made it keep the first occurrence. The speed is about the same and I think this behavior is useful in some cases. You might want to help test CVS or latest snapshot Previous Comments: ------------------------------------------------------------------------ [2002-01-16 18:41:27] pgerzson@freestart.hu Just one question: What the main goal to stick to preserving the first key when array_unique() eliminates multiple occurrences. I think in most cases it's not so important. ------------------------------------------------------------------------ [2002-01-16 17:43:45] venaas@php.net array_unique() uses qsort internally. Provided qsort doesn't change order of items that are equal, array_unique() should work as documented. Until recently the systems own qsort was used, giving different behavior on different systems. With latest PHP (in CVS) we use our own qsort which doesn't preserve order of equal items either. I'll either get that qsort changed, or I will write a new slower array_unique() that doesn't depend on qsort behavior. ------------------------------------------------------------------------ [2002-01-09 12:18:16] pgerzson@freestart.hu I tested the examples with PHP 4.1.1 on Apache 1.3.9 under debian stable. array_unique() does preserve the *first* key of every related value in this environment. Simone Cortesi <cortesi@php.net> stated on phpdoc list: " On my PHP Version 4.0.6 on System Windows 95/98 4.10 " (as it reads with phpinfo), I get... what I got, but " On the same machine using Cygwin and PHP/4.0.8-dev " I get: the expected result (returning with the first keys). ------------------------------------------------------------------------ [2002-01-02 13:20:30] pgerzson@freestart.hu I forgot to mention that there may be something wrong with array_unique itself. There are three values of 3 considered equal in the example above: 2 => "3"(string), 4 => 3(int), 5 => "3" (string) [manual] " Two elements are considered equal if and only if (string) " $elem1 === (string) $elem2. In words: when the string " representation is the same." Why does array_unique use the index 4 in this case? (It's neither the first nor the latest key of value 3) ------------------------------------------------------------------------ [2002-01-02 12:48:29] pgerzson@freestart.hu The manual (recent version from cvs) states that : " array_unique() will keep the first key encountered for every value, and ignore all following keys. " I've tested the two examples in this page and I've found this statement is not true. <?php $input = array (4,"4","3",4,3,"3"); $result = array_unique ($input); var_dump($result); ?> output: /* PHP 4.0.6 Win'98 PWS */ array(2) { [3]=> int(4) [4]=> int(3) } but the manual says it should print: array(2) { [0]=> int(4) [1]=> string(1) "3" } As you can recognize the latest keys are preserved for both value 4 and 3. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=14805&edit=1