Doubleval()

Introduction

The doubleval() function is a built-in function in PHP that converts a variable to a double (floating-point) number. It is similar to the floatval() function, which converts a variable to a float.

Syntax

The syntax of the doubleval() function is as follows:

double doubleval(mixed $var)

The function takes a single parameter, $var, which is the variable to be converted to a double. The function returns the double value of the variable, or 0.0 if the variable cannot be converted.

Example Usage

Here is an example of how to use the doubleval() function in PHP:

<?php
$var1 = "3.14159";
$var2 = 42;
$var3 = true;
$var4 = "not a number";
echo doubleval($var1) . "\n";  // output: 3.14159
echo doubleval($var2) . "\n";  // output: 42.0
echo doubleval($var3) . "\n";  // output: 1.0 (true is converted to 1.0)
echo doubleval($var4) . "\n";  // output: 0.0 (cannot convert "not a number" to a double)
?>

In this example, we define four variables with different data types: $var1 is a string, $var2 is an integer, $var3 is a boolean, and $var4 is a string that cannot be converted to a double. We then use the doubleval() function to convert each variable to a double and output the result. The output shows the double value of each variable, or 0.0 if the variable cannot be converted.

Conclusion

The doubleval() function is a useful tool for converting a variable to a double (floating-point) number in PHP. It can be used to convert strings, integers, and booleans to doubles, among other data types. By using this function, developers can ensure that their code is working with the correct data types and avoid errors that may occur when working with mixed data types.