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# empty

(PHP 3, PHP 4, PHP 5)

empty -- Determine 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 as a string)`
`NULL`
`FALSE`
`array() (an empty array)`
`var $var; (a variable declared, but without a value in a class)`

## ChangeLog

Version | Description
--- | ---
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.

## 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

## See Also

isset()
unset()
array_key_exists()
count()
strlen()
The type comparison tables

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