The unset Construct
The unset construct deletes a variable or a specified array element.
If the variable no longer exists after unset, the isset function will return false.
An attempt to access a deleted variable will generate a notice.
Syntax
unset($var);
unset($var1, $var2, $var3);
unset($array['key']);
Example
Deleting a simple variable:
<?php
$var = 'test';
unset($var);
var_dump(isset($var));
?>
Code execution result:
false
Example
Deleting an array element:
<?php
$arr = ['a', 'b', 'c'];
unset($arr[1]);
print_r($arr);
?>
Code execution result:
Array
(
[0] => a
[2] => c
)
Example
Deleting multiple variables:
<?php
$a = 1;
$b = 2;
$c = 3;
unset($a, $b, $c);
var_dump(isset($a), isset($b), isset($c));
?>
Code execution result:
false
false
false
