Difference between Char.IsDigit() and Char.IsNumber() in C#

Question

What's the difference between Char.IsDigit() and Char.IsNumber() in C#?

Answer 1

I found the answer:

Char.IsNumber() determines if a Char is of any numeric Unicode category. This contrasts with IsDigit, which determines if a Char is a radix-10 digit.

Valid numbers are members of the following categories in UnicodeCategory: DecimalDigitNumber, LetterNumber, or OtherNumber.

Answer 2

Char.IsDigit() is a subset of Char.IsNumeric().

Some of the characters that are 'numeric' but not digits include 0x00b2 and 0x00b3 which are superscripted 2 and 3 ('²' and '³') and the glyphs that are fractions such as '¼', '½', and '¾'.

Note that there are quite a few characters that IsDigit() returns true for that are not in the ASCII range of 0x30 to 0x39, such as the Thai digit characters that return true from Char.IsDigit(): '๐' '๑' '๒' '๓' '๔' '๕' '๖' '๗' '๘' '๙'

This snippet of code tells you which code points differ:

static private void test()
{
    for (int i = 0; i <= 0xffff; ++i)
    {
        char c = (char) i;

        if (Char.IsDigit( c) != Char.IsNumber( c)) {
            Console.WriteLine( "Char value {0:x} IsDigit() = {1}, IsNumber() = {2}", i, Char.IsDigit( c), Char.IsNumber( c));
        }
    }
}