empty
(PHP 4, PHP 5, PHP 7, PHP 8)
empty — Determine whether a variable is empty
Description
Determine whether a variable is considered to be empty. A variable is considered empty if it does not exist or if its value equals false. empty() does not generate a warning if the variable does not exist.
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.
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['0.5']));
var_dump(empty($expected_array_got_string['0 Mostel']));
?>
The above example will output:
bool(true) bool(false) bool(false) bool(false) bool(true) bool(true)
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.
See Also
- isset() - Determine if a variable is declared and is different than null
- __isset()
- unset() - Unset a given variable
- array_key_exists() - Checks if the given key or index exists in the array
- count() - Counts all elements in an array or in a Countable object
- strlen() - Get string length
- The type comparison tables
