PHP-manual | ||
---|---|---|
Föregående | Nästa |
Returns TRUE if var exists; FALSE otherwise.
If a variable has been unset with unset(), it will no longer be set. isset() will return FALSE if testing a variable that has been set to NULL. Also note that a NULL byte ("\0") is not equivalent to the PHP NULL constant.
Warning: isset() only works with variables as passing anything else will result in a parse error. For checking if constants are set use the defined() function.
<?php |
This also work for elements in arrays:
<?php |
Not: Eftersom detta �r en s� kallad language construct och inte en funktion kan den inte anropas med hj�lp av variabla funktioner
See also empty(), unset(), defined(), the type comparison tables, array_key_exists(), and the error control @ operator.
Föregående | Hem | Nästa |
is_string | Upp | print_r |