International PHP Conference 2015

empty

(PHP 4, PHP 5)

emptyDetermine whether a variable is empty

Description

bool empty ( mixed $var )

Determine whether a variable is considered to be empty.

Parameters

var

Variable to be checked

Note:

empty() only checks variables as anything else will result in a parse error. In other words, the following will not work: empty(trim($name)).

empty() is the opposite of (boolean) var, except that no warning is generated when the variable is not set.

Return Values

Returns FALSE if var has a non-empty and non-zero value.

The following things are considered to be empty:

  • "" (an empty string)
  • 0 (0 as an integer)
  • 0.0 (0 as a float)
  • "0" (0 as a string)
  • NULL
  • FALSE
  • array() (an empty array)
  • var $var; (a variable declared, but without a value in a class)

Changelog

Version Description
5.0.0

Objects with no properties are no longer considered empty.

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';
}
?>

Notes

Note: Because this is a language construct and not a function, it cannot be called using variable functions

Note:

When using empty() on inaccessible object properties, the __isset overloading method will be called, if declared.

See Also

add a note add a note

User Contributed Notes

There are no user contributed notes for this page.
To Top