PHP: Parsing a string as a float / decimal.

This is a short PHP tutorial on how to convert a string into a float or decimal variable. This can be important in cases where a PHP function expects a double variable.

Take the following error as an example:

Warning: deg2rad() expects parameter 1 to be double, string given in file.php on line 71

This warning was thrown because PHP’s deg2rad function was given a string variable when it expects a double value.

To fix this, we can simply parse the string as a float value by using the floatval function:

//A string containing a number.
$number = "2.392";

//var_dump it out and you will see that it is
//a string type.
var_dump($number);

//Use floatval to get the float value
//of our string variable
$number = floatval($number);

//Do another var_dump and you will see that
//it is now a float variable.
var_dump($number);

In the example above, we essentially extracted the float value from our string variable.

Instead of using the floatval function, you could also use type casting (aka type conversion):

//Using typecasting to parse
//the string as a float.
$number = (float) ($number);

In the example above, we used PHP’s type casting feature to cast our $number string as a float / decimal value.

Hopefully, you found this guide easy and straight-forward!