doubleval
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Variable handling Functions
PHP Manual

# empty

(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

doubleval
floatval
Variable handling Functions
PHP Manual