void unset ( mixed var [, mixed var [, mixed ...]] )
The unset( ) function deletes a variable so that isset( ) will return false. Once deleted, you can recreate a variable later on in a script.
<?
$name = "Paul";
if (isset($name)) print "Name is set\n";
unset($name);
if (isset($name)) print "Name is still set\n";
?>
That would print out "Name is set", but not "Name is still set", because calling unset( ) has deleted the $name variable.
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