On Thu, Nov 17, 2011 at 2:14 PM, Nidian Job-Smith <nidia...@hotmail.com>wrote:
> Hi all, > > I'm new to programming (thus Python), so after reading the > basics, I wanted to practise what I've learnt . I've come across a > beginners exercise which is to programme rot13. > > I've written some code but it doesn't seem to work.... > > Here it is: > > > def rot13(s): > char_low = () > result = "" > if not s.isalpha(): > return char > char_low = char_low.lower() > if char_low <= 'm': > dist = 13 > else: > dist = -13 > char = chr(ord(char) + dist) > > def rot13_char(ch): > return ''.join( rot13(s) for char in ch ) > > > Any idea where i'm wrong? > Please, when posting a program that has problems to this list, do not just say that "it doesn't work". Tell us what is wrong: * If you get a syntax error, tell us that, and tell us where it is claimed the syntax error is * if you get an error message, give the error message as well as the stack trace provided with it, or at least the last part of that stack trace * If the program does not crash, but behaves different from what you expected, tell us what you expected to get, and what you actually got (for example, "After giving the input 5 and 3 I had expected the program to output 8 and ask for a new pair of numbers, but instead it showed 8 lines of 8 stars, printed 'Thank you for using my program' and ended. Having said that, using your program gave me various problems. The first was in return ''.join( rot13(s) for char in ch ) - I got an error message that the name 's' was not defined. Reason: the variable before the for should be the same as after, so you should either say 'rot13(s) for s in ch' or 'rot13(char) for char in ch' Most of your other problems had the same cause: If you want to use something (a thing, a number, a letter, whatever), use the same name as you used when you defined that thing. -- André Engels, andreeng...@gmail.com
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