empty
(PHP 4, PHP 5, PHP 7, PHP 8)
empty — Determine whether a variable is empty
Parameters
var-
Variable to be checked
No warning is generated if the variable does not exist.
That means empty() is essentially the
concise equivalent to !isset($var) || $var == false.
This also applies to nested structures, such as a multidimensional array or chained properties.
Return Values
Returns true if var does not exist or has a value that is empty or equal to zero,
aka falsey, see conversion to boolean.
Otherwise returns false.
Examples
Example #1
A simple empty() / isset()
comparison.
<?php
$var = 0;
// Evaluates to true because $var is empty
if (empty($var)) {
echo '$var is either 0, empty, or not set at all';
}
// Evaluates as true because $var is set
if (isset($var)) {
echo '$var is set even though it is empty';
}
?>
Example #2 empty() on String Offsets
<?php
$expected_array_got_string = 'somestring';
var_dump(empty($expected_array_got_string['some_key']));
var_dump(empty($expected_array_got_string[0]));
var_dump(empty($expected_array_got_string['0']));
var_dump(empty($expected_array_got_string['0.5']));
var_dump(empty($expected_array_got_string['0 Mostel']));
?>
The above example will output:
bool(true)
bool(false)
bool(false)
bool(true)
bool(true)
Example #3 empty() on multidimensional arrays
<?php
$multidimensional = [
'some' => [
'deep' => [
'nested' => 'value'
]
]
];
if (!empty($multidimensional['some']['some']['nested'])) {
$someVariable = $multidimensional['some']['deep']['nested'];
}
var_dump(empty($multidimensional['some-undefined-key']));
var_dump(empty($multidimensional['some']['deep']['unknown']));
var_dump(empty($multidimensional['some']['deep']['nested']));
?>
The above example will output:
bool(true)
bool(true)
bool(false)
Notes
Note:
Because this is a
language construct and not a function, it cannot be called using
variable functions,
or named arguments.
Note:
When using empty() on inaccessible object properties,
the __isset()
overloading method will be called, if declared.
doubleval
Variable handling Functions