PHP Variable Handling doubleval() Function

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The PHP Variable Handling doubleval() function is used to return float value of a variable. This function is floatval()'s alias. It uses only one parameter which is a variable name defined in the program.

It can change textual or integer values to decimal numbers (floats). It is useful when you want to confirm that your data is in float format, particularly if performing calculations or working with numerical data.

Syntax

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

doubleval ( $variable_name )

Parameters

As indicated by the syntax above, this function takes one parameter, $variable_name. This parameter is needed. The name of the variable to be changed is given by this parameter. This parameter can be one of a mixed type, like a string, integer, etc.

Return Value

It returns back the given variable's float value.

• If empty array is passed, doubleval() returns 0.
• If non-empty array is passed, doubleval() returns 1.
• If non-empty array is passed, return 1.
• If String is passed, the doubleval() will most likely return 0 although this depends on the leftmost characters of the string.

PHP Version

First introduced in core PHP 4, the doubleval() 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 doubleval() function to get the float value of the given number.

<?php
// Define a variable here
$var = '51.76127E3'; 

// Use doubleval() function here
$double_value = doubleval($var);

// Print the value
echo "Float value of the given number is: ".$double_value; 
?>

Output

Here is the outcome of the following code −

Float value of the given number is: 51761.27

Example 2

In the below PHP code we will try to use the doubleval() function and get the float value of the given variable.

<?php
// Define a variable here
$var = '56.138mln'; 

// Use doubleval() function here
$double_value = doubleval($var);

// Print the value
echo "Float value of the given number is: ".$double_value; 
?> 

Output

This will generate the below output −

Float value of the given number is: 56.138

Example 3

Now the below code uses an empty and one non empty array to get the float values by using the doubleval() function and prints the values.

<?php
// Define an empty array
$emptyArray = [];

// Define a non empty array
$nonEmptyArray = [1, 2, 3];

// Use doubleval() on the arrays
$double_empty = doubleval($emptyArray);
$double_non_empty = doubleval($nonEmptyArray);

// Print the results
echo "Float value of the empty array: " . $double_empty . "\n";
echo "Float value of the non-empty array: " . $double_non_empty . "\n";
?> 

Output

This will create the below output −

Float value of the empty array: 0
Float value of the non-empty array: 1

Example 4

The doubleval() function converts variables into float values for mathematical operations. The code is below:

<?php
// Define variables
$num1 = "10.5";
$num2 = "2.3abc";
$array = [5, 10, 15];

// Use doubleval() in calculations
$result = doubleval($num1) * doubleval($num2) + doubleval($array);

// Print the result
echo "The result of the calculation is: " . $result;
?> 

Output

Following is the output of the above code −

The result of the calculation is: 25.15