Hi Glen, and welcome! My responses below.
On Thu, May 15, 2014 at 09:58:07PM -0400, Glen Chan wrote:
> Hello, I am student trying to fugure out why when I enter any number
> it says error. It's only suppose to do that if it's out the 1-10
> range. Please help. Thank you.
You've made an mistake in your logic below. You print an error for
*every* number:
> number = input('Enter a number between 1 and 10: ')
> while number < 1 or number > 10:
> print 'Please enter a number between 1 and 10'
> number = input('Enter a number between 1 and 10: ')
This part is okay. You check that if number is out of range, and if it
is, it prints a message. Check for yourself:
"Suppose I choose 5. Is 5 less than 1? No. Is it larger than
10? No. So the while loop immediately ends, and I move on."
So at this stage, you have now successfully asked the user for a number
between 1 and 10. But here you make the mistake:
> number = input('Enter a number between 1 and 10: ')
Hmmm. You've already asked the user for a number. But then you ignore
it, and ask for another one. But even that's not really the mistake:
> while number > 1 or number < 10:
> print 'Error'
> number = input('Enter a number between 1 and 10: ')
And this is where you get the logic backwards. This while loop runs
forever, or until you manually cancel it. Check for yourself:
"Suppose I choose 5. Is 5 larger than 1? Yes. So the while
loop continues, and 'Error' is printed. Suppose I choose 0.
Is 0 larger than 1? No. Is 0 less than 10? Yes. So again,
the while loop continues, and 'Error' is printed.
Are there *any* numbers *smaller* than 1 AND *larger* than
10 at the same time? No, of course not. So the while loop
condition is always true, and the while loop will always
run no matter what number I choose."
This second while loop has the logic backwards. You should compare this
one, the faulty one, with the first one, the correct one. Can you see
the difference?
A couple of other comments about your code:
* In a few places, you use "input", but in other places, you
use "raw_input". You should never use "input". It was a
mistake, and has been removed from newer versions of Python.
Instead, you should write int(raw_input("Enter a number...")).
* You check that number is in range like this:
number < 1 or number > 10
There's an easier way:
1 <= number <= 10
which is not only less typing, but makes it more obvious what
you are trying to do. You want number to be in the range 1
through 10 inclusive. That makes it harder to screw up the
logic:
1 >= number >= 10 # Wrong!
"What do you mean, 1 is BIGGER than number, which is bigger
than 10? That's impossible!"
--
Steven
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