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PHP is_null() Function

Syntax

is_null(variable);

Parameter Description
Variable Any variable (Required)

Example

<?php

$a = " NULL ";
if(is_null($a))
{
echo " Null ";	
}
else
{
echo " Not null ";
}

?>

Output

Not null

In above example $a is a variable and NULL is a string so that result will be not null. Double or single quotes represent the string.

Definition

It returns TRUE if the variable is NULL otherwise return false.

Usage

Is_null() function is used to check the variable is empty or not.

.

An undeclared $variable will return TRUE but may return an error.

Example of is_null function

<?php

$a="";

var_dump(is_null($a));

?>

In above example $a is a variable but not null so that result will be false.

More example of is_null function

<?php

$number = NULL;

var_dump(is_null($number));

$number1 = " John " ;

var_dump(is_null($number1));

?>

$number is a variable and NULL is not a string, its represent the variable with no value. SO result will be true.

$number is a string variable that hold some value so that result will be false.

All of these function works same as above.

  • is_array
  • is_bool
  • is_callable
  • is_double
  • is_float
  • is_int
  • is_integer
  • is_long
  • is_null
  • is_numeric
  • is_object
  • is_real
  • is_resource
  • is_scalar
  • is_string

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