First of all I'd like to thank you all for your advices. Before I check all your hints I want to clarify what I'm trying to do. The question says "write a function that takes a sequence of bits as an input and return how many 1s are in the sequence", nothing more. This is quite simple for string inputs but tricky for "number inputs". I've notice that if I try to convert a number starting with 0 to a string using str(), then I take a string representing another number (probably converted to decimal). So what I want to do is to write a generic version of a function that takes as an input a sequence of 1s and 0s in any format. The only way I can think to achieve that is by converting the "number inputs" to a string and then using the count() function. Thomas
-- http://mail.python.org/mailman/listinfo/python-list
