rookie question about python

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May 29th, 2004, 09:36 AM

python_begina

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rookie question about python

hi guys, im a relative beginner to the world of programming, i have done some very basic C++ programming before at college, but i decided to download python to learn some more about programming.
i have two questions-
the first:
im reading a few turtorials, but im stuck when it comes to making a calculator. i know it sounds really bad, but i just cant get it to print the answer. here is what ive done:

Code:

function = raw_input("a,m,t,d   ")
number1 = input("type a number here: ")
number2 = input("type a number here: ")

a = number1 + number2
m = number1 - number2
t = number1 * number2
d = number1 / number2
if function == a:
        a = number1 + number2
        answer = a
        print "the answer is", answer
elif function == m:
        m = number1 - number2
        answer = m
        print answer
elif function == t:
        t = number1 * number2
        answer = t
        print answer
elif function == d:
        d = number1 / number2
        answer = d
        print answer

could anyone help with this?

my second question is:
should i just give up and leave programming for the clever people, because i must admit , i have a very average inteligence level (IQ 95), and i must admit i find progamming pretty challenging. i am extremly interested in it though

thanks all

Last edited by netytan : May 29th, 2004 at 11:58 AM. Reason: Code Tags again

May 29th, 2004, 12:07 PM

netytan

Hello World :)

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Location: Hull, UK

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The problem is that your compating function (which is a string returned by raw_input()) to the answer resulting from four numeric expressions. As a result none of your if or elif statments are being executed. All you need to do here is to check for the strings 'a', 'm', 't' and 'd' instead i.e.

Code:

#!/usr/bin/env python

do = raw_input('a, b or c?')

if do == 'a':
    print 'you pressed a'
elif do == 'b':
    print 'you pressed b'
elif do == 'c':
    print 'you pressed c'
else:
    print 'I said, a, b or c not', do

You don't need to evaluate the same expersion more than once in your program, so you can loose these lines..

Quote:

a = number1 + number2
m = number1 - number2
t = number1 * number2
d = number1 / number2

you might also want to try using int(raw_input()) instead of input() in future since input() can be used to execute arbitary expessions - so in the right surcumstances, a big security risk

Mmmm, there answer to your second Q is even simpler. If you are interested in programming then program. Dont worry about not being as smart as the people around you since you'll never get anything done that way. Programming is an art, and as with all arts, takes a little time

. Give yourself a break! Have a KitKat

Good luck and for god sake have fun

,

Mark.

P.S. If you'd like to see the rewriten version of your program at all just ask.

__________________
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Last edited by netytan : May 29th, 2004 at 12:12 PM.

May 29th, 2004, 05:22 PM

python_begina

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thanks

thanks for the reply, i see where im going wrong now. im gonna keep at it until i get better and borrow a book from the library.

May 29th, 2004, 05:28 PM

python_begina

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oh and yes please, if thats ok, i would like a copy of the program re-written correctly, just make sure i fully understand it. thanks

May 29th, 2004, 05:38 PM

NetBSD

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Code:

function = raw_input("+, -, * or /: ")
number1 = int(raw_input("first number: "))
number2 = int(raw_input("second number: "))

if function == '+':
        answer = number1 + number2
elif function == '-':
        answer = number1 - number2
elif function == '*':
        answer = number1 * number2
elif function == '/':
        answer = number1 / number2

print "the answer is ", answer

May 29th, 2004, 09:55 PM

netytan

Hello World :)

Join Date: Mar 2003

Location: Hull, UK

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Code:

#!/usr/bin/env python

while True:
    function = raw_input('(a, s, m, d or q) --')

    try:
        number1 = int(raw_input("first number: "))
        number2 = int(raw_input("second number: "))
    except ValueError:
        'Please enter a number...try again!'

    if function == 'a':
        answer = number1 + number2
    elif function == 'b':
        answer = number1 - number2
    elif function == 'm':
        answer = number1 * number2
    elif function == 'd':
        try:
            answer = number1 / number2
        except ZeroDivisionError:
            print 'Can't divide by Zero...try again!'
    elif function == 'q':
        break
    else:
        'You must enter either (a, s, m, d or q)'

    print "the answer is ", answer

This should be pretty self explanitory if you have any experiance with error catching. Basically all thats happening here is were catching any forseeable errors. I've also added a while loop so that the program will keep asking you for untill you enter 'q'

.

You mgiht find this interesting when dealing with errors.

http://www.python.org/doc/current/l...exceptions.html

Have fun,

Mark.

May 30th, 2004, 04:50 AM

python_begina

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thanks guys.

rookie question about python

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