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empty

Podręcznik PHP
Poprzedni		Następny

empty

(PHP 3, PHP 4, PHP 5)

empty -- Determine whether a variable is empty

Opis

bool empty ( mixed var )

Determine whether a variable is considered to be empty.

Parametry

var

Variable to be checked

Notatka: 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.

Zwracane wartości

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 as a string)

NULL

FALSE

array() (an empty array)

var $var; (a variable declared, but without a value in a class)

Rejestr zmian

Wersja	Opis
PHP 5	As of PHP 5, objects with no properties are no longer considered empty.
PHP 4	As of PHP 4, The string value "0" is considered empty.

Przykłady

Przykład 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'; } ?>