#20708 [Com]: 'foo'==0 returns true

ID: 20708 Comment by: wb@sapo.pt Reported By: wb@sapo.pt Status: Bogus Bug Type: Scripting Engine problem Operating System: linux 2.2.20, linux 2.4.19 PHP Version: 4.2.3 New Comment: thank you for very fast information. type juggling is a great feature but really hard to learn. now i learned that it casts my string to numeric for the comparison with an integer - my coding would have needed the integer casted to a string. sorry for bothering you. i will go and look for more information about precedence of type casting in comparisons if it is that way it works. Previous Comments: ------------------------------------------------------------------------ [2002-11-28 18:13:07] rasmus@php.net The numerical value of 'foo' is 0. If you want to compare both value *and* type, use === ------------------------------------------------------------------------ [2002-11-28 18:11:16] wb@sapo.pt another summary ------------------------------------------------------------------------ [2002-11-28 18:02:32] wb@sapo.pt sorry, im really not sure if this is a kind of bug or if i'm getting something wrong: the two lines echo 'foo'==0 ? 'is true ' : 'is false '; if('bar'==0) echo 'is true '; else echo 'is false '; will output: is true is true i dont understand why 'foo'==0 returns true. the way i understand the manual, php should consider 'foo' a nonempty string and 0 a zero integer. even if it would do a boolean comparison, according to the manual 'foo' should be juggled to true and 0 should be juggled to false. how can 'foo'==0 return true? have i missed something? i hope i do not resubmit a known issue, i tried some queries but i really didnt know how to lookup this issue. this happens with variables as well. i ran into this problem in my programming when comparing array keys that could be numeric or string. a 0 array key compared against any nonempty string array key always returned true. it took me a while to find out that's why my program didn´t work the way i thought it should. i hope this is not something that happens only to me, but i have tested the two lines on three different boxes before writing to you. my configure line: ./configure' '--with-mysql=/usr/local/mysql' '--with-apache=../apache_1.3.26' '--enable-ftp' '--with-zlib-dir=/usr/lib' Best regards, wolfgang ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=20708&edit=1