> Can I use string formatting in my own functions, or is it stuck with > builtins?
No, you can use it too. > It doesn't make much sense for me, but I don't understand the following > error: > In [2]: def printd(arg): > ...: print('>>> %s') % arg The format operator needs to be with the string, inside the parentheses: def printd(arg): print('>>> %s' % arg) > TypeError: unsupported operand type(s) for %: 'NoneType' and 'int' The NoneType it refers to is the None returned by the function. In your code the function gets called then Python tries to apply string formatting to the result, which is None. HTH, Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor