Your first conversion works fine. string1 = '32' string2 = "%04s" % (string1) print string2 ' 32' Notice that it returns a string with spaces padding the left side. If you want to pad a number with 0's on the left you need to use zfill() '32'.zfill(4) '0032' Be sure to study up on string methods, it will save you time and sanity. Py> dir('') ['__add__', '__class__', '__contains__', '__delattr__', '__doc__', '__eq__', '__ge__', '__getattribute__', '__getitem__', '__getslice__', '__gt__', '__hash__', '__init__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__repr__', '__rmul__', '__setattr__', '__str__', 'capitalize', 'center', 'count', 'decode', 'encode', 'endswith', 'expandtabs', 'find', 'index', 'isalnum', 'isalpha', 'isdigit', 'islower', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'replace', 'rfind', 'rindex', 'rjust', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill'] Py> help(''.zfill) Help on built-in function zfill:
zfill(...) S.zfill(width) -> string Pad a numeric string S with zeros on the left, to fill a field of the specified width. The string S is never truncated. Hth, M.E.Farmer -- http://mail.python.org/mailman/listinfo/python-list