PHP/Data Type/unset
Содержание
Deleting an object
<source lang="html4strict">
class car {
function __destruct() { // head to car dealer }
} $car = new car; unset($car);
</source>
Removing Elements
<source lang="html4strict">
<?php
$dogs = array("A" => "AA", "Bud" => "BB","C" => "CC");printf("
%s\n", var_export($dogs, TRUE));
unset($dogs["C"]);printf("
%s\n", var_export($dogs, TRUE));
?>
</source>
Removing Elements from Arrays
<source lang="html4strict">
<?php $dogs = array("A" => "C", "B" => "D","X" => "Y", "Q" => "T"); printf("%s,", var_export($dogs, TRUE)); unset($dogs["X"]); printf("%s,", var_export($dogs, TRUE)); ?>
</source>
Removing Session Data
<source lang="html4strict">
<?
$_SESSION["foo"] = "bar"; print $_SESSION["foo"]; unset($_SESSION["foo"]);
?>
</source>
Using the unset() Function
<source lang="html4strict">
<?php
$myvar = "This is a string"; unset($myvar); // Destroy the variable
?>
</source>
void unset ( mixed var [, mixed var [, mixed ...]] )
<source lang="html4strict">
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.
</source>