note 78502 added to ref.array

Lately, dealing with databases, I've been finding myself needing to know if one array, $a, is a proper subset of $b. Mathematically, this is asking (in set theory) [excuse the use of u and n instead of proper Unicode): ( A u B ) n ( ~ B ) What this does is it first limits to known values, then looks for anything outside of B but in the union of A and B (which would be those things in A which are not also in B). If any value exists in this set, then A is NOT a proper subset of B, because a value exists in A but not in B. For A to be a proper subset, all values in A must be in B. I'm sure this could easily be done any number of ways but this seems to work for me. It's not got a lot of error detection such as sterilizing inputs or checking input types. // bool array_subset( array, array ) // Returns true if $a is a proper subset of $b, returns false otherwise. function array_subset( $a, $b ) { if( count( array_diff( array_merge($a,$b), $b)) == 0 ) return true; else return false; } ---- Server IP: 209.41.74.194 Probable Submitter: 209.155.240.195 ---- Manual Page -- http://www.php.net/manual/en/ref.array.php Edit -- https://master.php.net/note/edit/78502 Del: integrated -- https://master.php.net/note/delete/78502/integrated Del: useless -- https://master.php.net/note/delete/78502/useless Del: bad code -- https://master.php.net/note/delete/78502/bad+code Del: spam -- https://master.php.net/note/delete/78502/spam Del: non-english -- https://master.php.net/note/delete/78502/non-english Del: in docs -- https://master.php.net/note/delete/78502/in+docs Del: other reasons-- https://master.php.net/note/delete/78502 Reject -- https://master.php.net/note/reject/78502 Search -- https://master.php.net/manage/user-notes.php