Check if value isset and null
See Best way to test for a variable's existence in PHP; isset() is clearly broken
if( array_key_exists('foo', $GLOBALS) && is_null($foo)) // true & true => true
if( array_key_exists('bar', $GLOBALS) && is_null($bar)) // false & => false
If you are dealing with object properties which might have a value of NULL you can use: property_exists()
instead of isset()
<?php
class myClass {
public $mine;
private $xpto;
static protected $test;
function test() {
var_dump(property_exists($this, 'xpto')); //true
}
}
var_dump(property_exists('myClass', 'mine')); //true
var_dump(property_exists(new myClass, 'mine')); //true
var_dump(property_exists('myClass', 'xpto')); //true, as of PHP 5.3.0
var_dump(property_exists('myClass', 'bar')); //false
var_dump(property_exists('myClass', 'test')); //true, as of PHP 5.3.0
myClass::test();
?>
As opposed with isset(), property_exists() returns TRUE even if the property has the value NULL.
IIRC, you can use get_defined_vars()
for this:
$foo = NULL;
$vars = get_defined_vars();
if (array_key_exists('bar', $vars)) {}; // Should evaluate to FALSE
if (array_key_exists('foo', $vars)) {}; // Should evaluate to TRUE