Variable handling Funkcje

is_null

(PHP 4 >= 4.0.4, PHP 5)

is_null — Finds whether a variable is NULL

Opis

bool is_null ( mixed $var )

Finds whether the given variable is NULL.

Parametry

var: The variable being evaluated.

Zwracane wartości

Returns TRUE if var is null, FALSE otherwise.

Przykłady

Przykład #1 is_null() example


<?php

error_reporting(E_ALL);

$foo = NULL;
var_dump(is_null($inexistent), is_null($foo));

?>

Notice: Undefined variable: inexistent in ...
bool(true)
bool(true)

Zobacz też:

The NULL type
isset() - Determine if a variable is set and is not NULL
is_bool() - Finds out whether a variable is a boolean
is_numeric() - Finds whether a variable is a number or a numeric string
is_float() - Finds whether the type of a variable is float
is_int() - Find whether the type of a variable is integer
is_string() - Find whether the type of a variable is string
is_object() - Finds whether a variable is an object
is_array() - Finds whether a variable is an array

Variable handling Funkcje