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Python

Posted by AJ Longstreet
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AJ Longstreet
Treehouse Project Reviewer

Hmm, Python while loop not working.

I was wondering if I could get a bit of advice. For some reason, my if statement is not working correctly. Regardless of what input I give it just calls the step9() function.

while True: print("Addition and Multiplication") print("(A)dd, (M)ultiply")

choice = input(" > ")

if choice is not "A" or "M":
    step9()
elif choice is "A":
    add()
elif choice is "M":
    mult()
else:
    break

Thanks, AJ

AJ Longstreet
.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer

First hurdle cleared.

Changed to 

if choice not in ("A" or "M"):
    step9()

Now to fix the rest.... lol

2 Answers

Steven Parker
Steven Parker
243,318 Points
Steven Parker
Steven Parker
243,318 Points

Cleared .... are you sure?

I don't think that test will do what you think. I assume you want to test if the the input was anything other than an "A" or an "M". You could do it either of these ways, though:

if choice not in ("A", "M"):  # with a tuple
if choice not in ["A", "M"]:  # with a list

Then next, you are using the identity comparison ("is") where you want an equality comparison ("=="). The choice might have the same value (equality) as the literal string, but it will never be the same thing (identity).

AJ Longstreet
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.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer
AJ Longstreet
.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer

OK, I'll try that out as I try to get it working in Python 3. This works perfectly for me in Python 2.7. I'm going to see if I can optimize it and make it work in either version.

n1 = 0
n2 = 0
np = 0
choice = "string"

def add():
    n1 = input("Please enter a number > ")
    n2 = input("Please enter your second number > ")
    np = n1 + n2
    print("Sum is " + str(np))

def mult():
    n1 = input("Please enter a number > ")
    n2 = input("Please enter your second number > ")
    np = n1 * n2
    print("Product is " + str(np))

def step9():
    print("Choose A or M")

while True:
    print("Addition and Multiplication")
    print("(A)dd, (M)ultiply or (D)ONE to exit")

    choice = raw_input(" > ")

    if choice in ("A" or "M"):
        step9()
    if choice is "A":
        add()
    if choice is "M":
        mult()
    if choice is "D":
        break

print("Good Bye")