float
The float function returns a real number from a number or a text string.
If the argument is a text string, it should contain the decimal point (though not required, see example below), optionally preceded by a sign. If no argument is added, the function returns the real number 0.0. The argument can also be a text string representing a "nan" (not a number) or a positive or negative infinity. More exactly, the argument must comply with the following grammar after removing whitespaces at the beginning and end of the string: