C# Parse a Number from Exponential Notation

Question

I need to parse the string "1.2345E-02" (a number expressed in exponential notation) to a decimal data type, but Decimal.Parse("1.2345E-02") simply throws an error

Answer 1

Try parsing it as a double, then cast to decimal.

If doesn't work, roll-your-own parser?

Answer 2

It is a floating point number, you have to tell it that:

decimal d = Decimal.Parse("1.2345E-02", System.Globalization.NumberStyles.Float);

Answer 3

It works if you specify NumberStyles.Float:

decimal x = decimal.Parse("1.2345E-02", NumberStyles.Float);
Console.WriteLine(x); // Prints 0.012345

I'm not entirely sure why this isn't supported by default - the default is to use NumberStyles.Number, which uses the AllowLeadingWhite, AllowTrailingWhite, AllowLeadingSign, AllowTrailingSign, AllowDecimalPoint, and AllowThousands styles. Possibly it's performance-related; specifying an exponent is relatively rare, I suppose.

Answer 4

    static void Main(string[] args)
    {
        decimal d = Decimal.Parse("1.2345E-02",
                                  System.Globalization.NumberStyles.Float);

    }