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empty (PHP 3, PHP 4, PHP 5) empty -- Determine whether a variable is empty Descriptionbool 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) |
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';
}
?> |
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NotesNote: Because this is a
language construct and not a function, it cannot be called using
variable functions
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doubleval
