#8353 [Opn]: foreach modify array pointer

ID: 8353 Updated by: philip@php.net Reported By: lunepi@comlink.org Status: Open -Bug Type: Arrays related +Bug Type: Documentation problem PHP Version: 4.4.0-dev -Assigned To: +Assigned To: philip New Comment: The foreach() page will be updated and made more clear on this behavior. Regarding the pointer, foreach() indeed behaves like while/each() (except for the initial reset) and moves the pointer past the end. So although it provides a copy to work with it still affects the original arrays pointer! Previous Comments: ------------------------------------------------------------------------ [2002-11-27 10:32:33] philip@php.net As I've been taught, foreach doesn't affect the pointer as it merely works on a copy. Also, the following note exists in the foreach() entry of the manual and has for over two years: Note: Also note that foreach operates on a copy of the specified array, not the array itself, therefore the array pointer is not modified as with the each() construct and changes to the array element returned are not reflected in the original array. That was added by Sterling here: http://cvs.php.net/diff.php/phpdoc/en/language/control-structures.xml?login=2&r1=1.9&r2=1.10&ty=h Everyone assumes foreach works on a copy and only a copy. IMHO each() isn't a fair comparison because it doesn't work on a copy. ------------------------------------------------------------------------ [2002-11-24 23:10:40] iliaa@php.net IMO this is not a bug. Foreach works virtually like while + each combination, with a few exceptions such as not requiring a reset() prior to execution since it does not care about the current position in the array. As far as current(), next() and simular are concerned, while (each($arr)); == foreach ($arr as $v);, once the loops are complete current() will return FALSE. This IMO is a consistent behaviour and is definately not a bug. I believe this is merely a documentation issue. ------------------------------------------------------------------------ [2002-11-21 15:21:34] philip@php.net foreach essentially REMOVES the array pointer alltogether on the original array. $arr = array('a','b'); foreach ($arr as $v); var_dump( current($arr) ); $arr = array('a','b'); foreach ($arr as $v); reset($arr); var_dump( current($arr) ); Results: bool(false) string(1) "a" Using key() instead of current() results in NULL instead of false. Where did the pointer go? Conclusion: Either foreach() has a feature that removes the array pointer from the original array or it's a bug. If it's seen as a feature please explain why so it can be documented. ------------------------------------------------------------------------ [2001-03-09 21:32:57] sniper@php.net no feedback. ------------------------------------------------------------------------ [2001-01-05 22:52:10] sniper@php.net I get 121 for both cases. Please try the latest snapshot from http://snaps.php.net/ --Jani ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/8353 -- Edit this bug report at http://bugs.php.net/?id=8353&edit=1