Finds whether a variable is NULL
Variable handling Functions
PHP Manual

is_null

(PHP 4 >= 4.0.4, PHP 5)

is_null — Finds whether a variable is NULL

Description

bool is_null ( mixed $var )

Finds whether the given variable is NULL.

Parameters

var

The variable being evaluated.

Return Values

Returns TRUE if var is null, FALSE otherwise.

Examples

Example #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)

See Also

  • 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 Functions
PHP Manual
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