w3resource

PHP: is_null() function

Description

The is_null () function is used to test whether a variable is NULL or not.

Version:

(PHP 4 and above)

Syntax:

is_null (var_name)

Parameter:

Name Description Required /
Optional		 Type
var_name The variable being checked Required Mixed*

*Mixed: Mixed indicates that a parameter may accept multiple (but not necessarily all) types.

Return value:

Returns TRUE if var_name is null, FALSE otherwise.

Value Type: Boolean

Example:

<?php
$var_name = TRUE;
if (is_null($var_name))
{
echo 'Variable is  NULL';
}
else
{
echo 'Variable is not NULL';
}
?>

Output:

Variable is not NULL

View the example in the browser

Practice here online:

See also

PHP Function Reference

Previous: is_long
Next: is_numeric



PHP: Tips of the Day

Returns true if the given string is a palindrome, false otherwise

Example:

<?php
function tips_palindrome($string)
{
  return strrev($string) === (string) $string;
}

print(tips_palindrome('malayalam'));
print("\n");
print(tips_palindrome(151));

?>

Output:

1
1