<https://schoolsofweb.com/php/function-list/variable-handling/is_float/#webpage>
<http://schema.org/description>
"If you want to check whether a value is of float type or not, use is_float() function. Instead of using value directly, you can use a variable to check its type too."
<https://schoolsofweb.com/php/function-list/variable-handling/is_float/>