On Sun, Mar 25, 2012 at 4:11 PM, Arno Kuhl <a...@dotcontent.net> wrote: > From: Simon Schick [mailto:simonsimc...@googlemail.com] > Sent: 24 March 2012 12:30 AM > To: Robert Cummings > Cc: a...@dotcontent.net; php-general@lists.php.net > Subject: Re: [PHP] foreach weirdness > > 2012/3/23 Robert Cummings <rob...@interjinn.com> >> >> On 12-03-23 11:16 AM, Arno Kuhl wrote: >>> >>> >>> it still does not produce the correct result: >>> 0 1 3 6 10 15 21 >>> 0 1 3 6 10 15 15 >> >> >> This looks like a bug... the last row should be the same. What version >> of PHP are you using? Have you checked the online bug reports? >> >> > > Hi, Robert > > Does not seem like a bug to me ... > http://schlueters.de/blog/archives/141-References-and-foreach.html > > What you should do to get the expected result: > Unset the variable after you don't need this reference any longer. > > Bye > Simon > > -- > > Hi Simon, unsetting the $value does fix the problem, but I found that any > time you assign $value by reference in a foreach loop you have to do an unset > to avoid corrupting the array unless you continue to assign $value by > reference (as illustrated in the article you linked). > > So doing something as simple as: > $array = array(0, 1, 2, 3, 4, 5, 6); > foreach ($array as $key=>&$value) { > echo "Key: $key; Value: $value<br />\n"; > } > > and then follow with (from the php manual): > foreach ($array as $key=>$value) { > echo "Key: $key; Value: $value<br />\n"; > } > > will not only give the wrong result, it will corrupt the array for *any* > further use of that array. I still think it’s a bug according to the > definition of foreach in the php manual. Maybe php needs to do an implicit > unset at the closing brace of the foreach where was an assign $value by > reference, to remove the reference to the last element (or whatever element > it was pointing to if there was a break) so that it doesn't corrupt the > array, because any assign to $value after the foreach loop is completed will > corrupt the array (confirmed by testing). The average user (like me) wouldn't > think twice about reusing $value after ending the foreach loop, not realising > that without an unset the array will be corrupted. > > BTW thanks for that reference, it was quite an eye-opener on the pitfalls of > using assign by reference, not only in the foreach loop. > > Cheers > Arno
Note that somewhat similar error was discussed on this list a few months ago[1]. You could probably have solved it yourself if you searched the mailing list archives. - Matijn [1] http://www.mail-archive.com/php-general@lists.php.net/msg269552.html -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
