Diana Hawksworth said unto the world upon 2005-04-16 17:39:
<SNIP>
> Diana Hawksworth said unto the world upon 2005-04-15 22:25: > > Hello list, > > > > I have been trying to trap a string entry by raising an exception.
The
code follows - but the exception is never raised. What am I doing
wrong?
> > > > TIA Diana > > > > try: > > > > self.guess = int(self.num_ent.get()) > > > > self.num_ent.delete(0,END) > > self.num_ent.focus_set() > > > >
- Ignored: > > if self.guess < self.number: > > message = str(self.guess) + " is too low. You need
to
guess higher" > > > > if self.guess > self.number: > > message = str(self.guess) + " is too high. You
need to
guess lower" > > > > if self.guess == self.number: > > message = str(self.guess) + " is the correct
number!"
> > self.message_txt.config(state = NORMAL) > > self.message_txt.config(state = DISABLED) > > > > self.message_txt.config(state = NORMAL) > > self.message_txt.delete(0.0, END) > > self.message_txt.insert(0.0, message) > > self.message_txt.config(state = DISABLED) > > > > > > except(ValueError): > > message = str(self.guess) + " is not a number. Please try again!" > > > > Hi Dianna, > > What are you expecting to raise the ValueError? It looks to me like
it
> must be the line: > > self.guess = int(self.num_ent.get()) > > But, if that is so, then the assignment to message in your except > clause won't work, as self.guess won't have been assigned. > > I'm no expert, so I may be missing something, but I wouldn't be > surprised if your num_ent.get() has details that are pertinent. What > does that method return? >
<SNIP my suggestion to use string formatting>
> > Best, > > Brian vdB > > Thanks for your reply Brian. The num_ent.get() method returns a
number.
Actually, it is an Entry box that returns a string, that I then
convert to
an integer. What I would like to do, is, if a user enters a string,
to have
the program return an exception. At the moment it just blithely
carries on
as if the string that was entered was in fact an integer, and compares
that
entered string to a random number!
Hi Diana,
hm, our mail clients between them appear to have made a mess of the quoting :-( This makes it a bit harder to parse the code, but let's try.
I'm still not 100% clear on the role of
self.guess = int(self.num_ent.get())
in your code. Does self.num_ent.get() return a string or an integer? Perhaps I'm misreading, but you seem to say both. Your second comment is that "it is an Entry box that returns a string" -- I assume you mean that at some point it calls the raw_input function, right?
What happens if you enter something like "I am not a number!" at that point in the run of self.num_ent.get? If self.num_ent.get() really just returns a string, then I'd expect roughly the same thing as what happens below:
>>> my_input = raw_input("Well?\n")
Well?
I am not a number!
>>> int(my_input)Traceback (most recent call last):
File "<pyshell#2>", line 1, in -toplevel-
int(my_input)
ValueError: invalid literal for int(): I am not a number!
>>>I think it would help if you posted the code for the num_ent.get method. Otherwise, I at least, am out of stuff to say :-)
(If you post again, please delete the goofy-formatted code quote above, and replace with a new copy-paste from your source.)
Thanks for the hint on string formatting! I had forgotten about that!
Been doing
this for a month only!!!
Thanks again. Diana
Your welcome. There is a lot to keep in one's head at the beginning, isn't there? My money is on the claim that string formatting is a good habit to get into early.
Best,
Brian vdB
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