unset — Unsets one or more variables.
void unset(variable[, another_variable][, . . .]);
mixed variable: Variable to
(optional): Another variable to unset
mixed . . . (optional):
unset() deletes one or more variables. The
function returns nothing - attempting to assign its
return value to a variable simply results in PHP
generating a parse error. If you want to ensure that the
value has been deleted, use the isset() function.
PHP Version: 3+, 4+
Example 1410. Use
$song = array (
'name' => 'Another Second to Be',
'band' => 'Accept',
'album' => 'Russian Roulette',
'year' => 1986
print "<tt>$song</tt> before calling unset:\n";
// Individual array elements can be unset
print "\n<tt>\$song</tt> after calling <tt>unset (\$song['year']):</tt>\n";
print "\n<tt>\$song</tt> after calling <tt>unset (\$song):</tt>\n";
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing
(Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch).
This material may be distributed only subject to the terms and conditions set forth
in the Open Publication License, v1.0 or later (the latest version is presently available at
The authors of this book have elected not to choose any options under the OPL. This online book was obtained
and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4
for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All
persons and entities shall have neither liability nor responsibility to any person or entity with respect to
any loss or damage arising from the information contained in this book.