[Tutor] new to python error handling question

[Alan Gauld]

Erick,

I think you maybe need to slow down and take a few steps back here.
There are a few weird things in your code that suggest you don't
really understand whats happening and that will lead to problems
later.

BTW YOu don;t say if you have any previous programming experience
in other languages? If so that helps us phrase our responses.

>   def do_list(*??*):

The *??* is where you pass in values that your function will use.
In this function a sensible thing wouyld be the address used by
the ftp.retrlines call

def do_list(address):

>         try:
>             ftp.retrlines("list")

You would then use the address parameter in here

              ftp.retrlines(address)

>             pass

You don't need this it literally does nothing!

>         except (AttributeError):

This checks for an AttributeError being raised in the previous
try section. BTW I donlt think you need the parens around
AttributeError.
If the try/except was missed out the error would be passed back
to Python and it would print an error message.

>             print "AttributeError"
>             pass

Again the pass does nothing

>         return ()

And this returns an empty tuple to the caller, which is probably not
what you want?

> Why does it for sure detect AttributError when
> if i take the Try,Except off, it does'nt.

Dunno, can you show/tell us what you do get without the try/except?

It looks like you need to read the bit about defining functions
in your tutorial (whichever it is) soince you seem confused about
how they work. Also the try/except stuff. Both are covered in my
web tutor if you can't find it elsewhere, look under
"Modules & Functions" and "Error Handling"

Alan G
Author of the Learn to Program web tutor
http://www.freenetpages.co.uk/hp/alan.gauld