PHP Variable Handling boolval() Function

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The PHP Variable Handling boolval() function is used to get the boolean value of a variable. So it returns a boolean value either true or false. It only accepts one parameter which can be an expression or the scalar that you want to change into boolean value. The method is useful for converting numerous types of values (including numbers, messages, and arrays) to a basic true or false format.

This function is very simple and works with all data types like numbers, strings, arrays, objects and more. It was added in PHP version 5.5.0 and works in all newer versions fo PHP.

Syntax

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

bool boolval( mixed $value )

Parameters

This function accepts $value parameter which the expression or scalar that you want to convert into a boolean value. It could be a string type, an integer type, and so on.

Return Value

The boolval() function returns a boolean value (TRUE or FALSE). Below is a list of different variable types and their return value (TRUE or FLASE) on conversion to boolean value −

• integer: if value is 0 then boolval() returns false. For any other value returns true.

• float: if value is 0.0 then boolval() returns false. For any other value returns true.

• string: if string value is "0" and null then boolval() returns false. For any other value returns true (even "0.0").

• array: if value is empty array then boolval() returns false. For any other value returns true.

• object: if object is null then boolval() returns false. For any other value returns true.

• null: boolval() always returns false when variable is null.

PHP Version

The boolval() function was first introduced as part of core PHP 5.5.0 and work well with the PHP 7, PHP 8.

Example 1

First we will show you the basic example of the PHP Variable Handling boolval() function to convert an integer to a boolean and prints the output.

<?php
   // Mention a number here
   $number = 10;

   // Use boolval() function to get its boolean value
   $result = boolval($number);

   // Print the result
   echo "The boolean value of $number is " . ($result ? 'true' : 'false') . ".\n";
?>

Output

Here is the outcome of the following code −

The boolean value of 10 is true.

Example 2

In the below PHP code we will try to use the boolval() function and convert a string to a boolean.

<?php
   $text = "Hello, World!";

   $result = boolval($text);

   echo "The boolean value of '$text' is " . ($result ? 'true' : 'false') . ".\n";
?> 

Output

This will generate the below output −

The boolean value of 'Hello, World!' is true.

Example 3

In the following example you can see how boolval() treats 0 as false.

<?php
   $zero = 0;

   $result = boolval($zero);

   echo "The boolean value of $zero is " . ($result ? 'true' : 'false') . ".\n";
?> 

Output

Following is the output of the above code −

The boolean value of 0 is false.

Example 4

Following example demonstrates return values with different types of variables −

<?php
   // PHP program demo for boolval() function
   echo 'boolval of 4: '.( boolval( 4 )? 'true' : 'false');
   echo 'boolval of -4: '.( boolval( -4 )? 'true' : 'false');
   echo 'boolval of 0: ' .( boolval( 0 )? 'true' : 'false');
   echo 'boolval of 4.5: '.( boolval( 4.5 )? 'true' : 'false');
   echo 'boolval of -4.5: '.( boolval( -4.5 )? 'true' : 'false' );
   echo 'boolval of 0.0: '.( boolval( 0.0 )? 'true' : 'false' );
   echo 'boolval of "1": '.( boolval( "1" )? 'true' : 'false' );
   echo 'boolval of "0": '.( boolval( "0" )? 'true' : 'false' );
   echo 'boolval of "0.0": '.( boolval( "0.0" )? 'true' : 'false' );
   echo 'boolval of "abc": '.( boolval( "abc" )? 'true' : 'false' );
   echo 'boolval of "": '.( boolval( "" )? 'true' : 'false' );
   echo 'boolval of [2, 3]: '.( boolval( [1, 5] )? 'true' : 'false' );
   echo 'boolval of []: '.( boolval( [] )? 'true' : 'false' );
   echo 'boolval of NULL: '.( boolval( NULL )? 'true' : 'false' );
?> 

Output

This will create the below output −

boolval of 4: true
boolval of -4: true
boolval of 0: false
boolval of 4.5: true
boolval of -4.5: true
boolval of 0.0: false
boolval of "1": true
boolval of "0": false
boolval of "0.0": true
boolval of "abc": true
boolval of "": false
boolval of [2, 3]: true
boolval of []: false
boolval of NULL: false