the number in a uinteger
Exception in case string is not a hexadecimal number, or too big to store in uinteger, or empty string
assert("FF".readHexadecimal == 0xFF); assert("F0".readHexadecimal == 0xF0); assert("EF".readHexadecimal == 0xEF); assert("A12f".readHexadecimal == 0xA12F);
Reads a hexadecimal number from string