PHP. Руководство по PHP. 2005
empty
empty
Описание
bool empty (mixed var)Determine whether a variable is considered to be empty.
empty
Determine whether a variable is considered to be empty.
var
Variable to be checked
Замечание: 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.
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) |
| Версия | Описание |
|---|---|
| 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. |
|
Пример 1. A simple empty() / isset() comparison.
|
Замечание: Поскольку это языковая
конструкция, а не функция, она не может вызываться при помощи
| isset() |
| unset() |
| array_key_exists() |
| count() |
| strlen() |
| The type comparison tables |
doubleval
floatval
Отвечу на любые вопросы. С уважением, Дмитрий Владимирович.
⇪