PHP Variable Handling is_array() Function

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The PHP Variable Handling is_array() function is used to check whether a variable is in an array. An array is a collection of data stored in a single variable. When you call this function, it checks whether the variable you given is an array or not. If the variable is an array, the function returns true. Otherwise, it returns false.

This is useful when you want to check the type of a variable before performing any operations with it. The function simply takes one parameter: the variable to be verified. It can be used in a variety of situations where you must make sure that a variable includes an array.

Syntax

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

bool is_array ( mixed $value )

Parameters

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

Return Value

The is_array() function returns TRUE if value is an array. Otherwise it will return FALSE.

PHP Version

First introduced in core PHP 4, the is_array() function continues to function easily in PHP 5, PHP 7, and PHP 8.

Example 1

This basic example for showing the usage of the PHP Variable Handling is_array() function and check if the variable $value is an array. As $value is an array, the output will be "This is an array."

<?php
   $value = array(1, 2, 3);
   if (is_array($value)) {
      echo "This is an array.";
   } else {
      echo "This is not an array.";
   }
?>

Output

Here is the outcome of the following code −

This is an array.

Example 2

In the below PHP code we will use the is_array() function and check the false value means if we provide string to the function so it whould return false.

<?php
   $value = "Hello, world!";
   if (is_array($value)) {
      echo "This is an array.";
   } else {
      echo "This is not an array.";
   }
?> 

Output

This will generate the below output −

This is not an array.

Example 3

Now the below code defines a function 'checkArray' to verify if the input is an array. It returns a message as per the input if it is an array or not. The function is called two times with different types of data.

<?php
   function checkArray($input) {
      if (is_array($input)) {
         return "It's an array!";
      } else {
         return "It's not an array.";
      }
   }

   echo checkArray([1, 2, 3]); 
   echo checkArray("Text"); 
?> 

Output

This will create the below output −

It's an array!
It's not an array.

Example 4

This example uses a multidimensional array, where friends representing an array within the primary array. The is_array function is called two times: once to make sure that $data is an array and again to find out whether the value of the 'friends' key is also an array.

<?php
   $data = array(
      "name" => "John",
      "age" => 25,
      "friends" => array("Mike", "Sara")
   );

   if (is_array($data)) {
      echo "This is an array.\n";
      if (is_array($data['friends'])) {
         echo "Friends is also an array.\n";
      }
   } else {
      echo "This is not an array.\n";
   }
?> 

Output

Following is the output of the above code −

This is an array.
Friends is also an array.