PHP Variable Handling is_scalar() Function

The PHP Variable Handling is_scalar() function is used to check whether a value is scalar. A scalar is a simple value like a number, text or boolean. It includes arrays, objects, and other types like resources.

This function checks if a value is simple or complex. It returns true if the value is a scalar. It returns false if the value is not a scalar. It is useful for working with different types of data. It checks that the value is simple before using it.

Syntax

Below is the syntax of the PHP Variable Handling is_scalar() function −

bool is_scalar ( mixed $value )

Parameters

This function accepts $value parameter which is the variable to be evaluated.

Return Value

The is_scalar() function returns TRUE if the value is a number, string or boolean. And it returns FALSE if the value is an array, object, resource or NULL.

PHP Version

First introduced in core PHP 4.0.5, the is_scalar() function continues to function easily in PHP 5, PHP 7, and PHP 8.

Example 1

First we will show you the basic example of the PHP Variable Handling is_scalar() function to check if a number is scalar. As numbers are scalar values so the function will return true.

<?php
   // A number
   $value = 10; 
   if (is_scalar($value)) {
      echo "The value is scalar.";
   } else {
      echo "The value is not scalar.";
   }
?>

Output

Here is the outcome of the following code −

The value is scalar.

Example 2

In the below PHP code we will use the is_scalar() function and check different values like a string, a boolean and an array. Strings and booleans are scalar but arrays are not.

<?php
   // Different data types   
   $values = [32, "Hello", true, [1, 2, 3]]; 

   foreach ($values as $value) {
      echo (is_scalar($value) ? "Scalar" : "Not Scalar") . " - " . var_export($value, true) . "";
   }
?> 

Output

This will generate the below output −

Scalar - 32
Scalar - 'Hello'
Scalar - true
Not Scalar - array (
  0 => 1,
  1 => 2,
  2 => 3,
)

Example 3

Now the below code uses the is_scalar() function to check variables in a user defined function. So we will use a function to check multiple values and display whether they are scalar or not.

<?php
   function checkScalar($value) {
      if (is_scalar($value)) {
         echo "The value " . var_export($value, true) . " is scalar.\n";
      } else {
         echo "The value is not scalar.\n";
      }
   }

   checkScalar(3.14);      
   checkScalar("PHP");     
   checkScalar(false);     
   checkScalar(NULL); 
?> 

Output

This will create the below output −

The value 3.14 is scalar.
The value 'PHP' is scalar.
The value false is scalar.
The value is not scalar.

Example 4

In the following example, we are using the is_scalar() function to show how the function works with different kinds of values.

<?php
   $a = "Tutorialspoint";
   echo "a is ".( is_scalar($a)? 'scalar' : 'not scalar') . "\n";

   $b = 0;
   echo "b is ".( is_scalar($b)? 'scalar' : 'not scalar') . "\n";

   $c = 40;
   echo "c is ".( is_scalar($c)? 'scalar' : 'not scalar') . "\n";

   $d = NULL;
   echo "d is ".( is_scalar($d)? 'scalar' : 'not scalar') . "\n";

   $e = array("a", "b", "c");
   echo "e is ".( is_scalar($e)? 'scalar' : 'not scalar') . "\n";

   $f = 3.1416;
   echo "f is ".( is_scalar($f)? 'scalar' : 'not scalar') . "\n";

   $g = new stdClass();
   echo "g is ".( is_scalar($g)? 'scalar' : 'not scalar') . "\n";  
?> 

Output

Following is the output of the above code −

a is scalar
b is scalar
c is scalar
d is not scalar
e is not scalar
f is scalar
g is not scalar