Beginner in Functions (python)

thorbarry

Hey guys,

learning python on a on-line tutorial. this example doesn't seem to work (just keeps looping back the initial menu).

can someone advise?

thank you

def menu():
    #print what options you have
    print ("Welcome to calculator.py")
    print ("your options are:")
    print (" ")
    print ("1) Addition")
    print ("2) Subtraction")
    print ("3) Multiplication")
    print ("4) Division")
    print ("5) Quit calculator.py")
    print (" ")
    
    return input ("Choose your option: ")
print (menu())
   
# this adds two numbers given
def add(a,b):
    print (a, "+", b, "=", a + b)
    
# this subtracts two numbers given
def sub(a,b):
    print (b, "-", a, "=", b - a)
    
# this multiplies two numbers given
def mul(a,b):
    print (a, "*", b, "=", a * b)
    
# this divides two numbers given
def div(a,b):
    print (a, "/", b, "=", a / b)
    
# NOW THE PROGRAM REALLY STARTS, AS CODE IS RUN
loop = 1
choice = 0

    
while loop == 1:
    choice = (menu())
    if choice == 1:
        add(input("Add this: "),input("to this: "))
    elif choice == 2:
        sub(input("Subtract this: "),input("from this: "))
    elif choice == 3:
        mul(input("Multiply this: "),input("by this: "))
    elif choice == 4:
        div(input("Divide this: "),input("by this: "))
    elif choice == 5:
        loop = 0

print ("Thankyou for using calculator.py!")

duffman85

you're nearly have it...

read up on the input function in the python documentation http://docs.python.org/3.3/library/functions.html
For future reference surround your code with

tags, especially with a language like python where the spaces/tabs are important.

Here's your code reformatted:
[code]
def menu():
    #print what options you have
    print ("Welcome to calculator.py")
    print ("your options are:")
    print (" ")
    print ("1) Addition")
    print ("2) Subtraction")
    print ("3) Multiplication")
    print ("4) Division")
    print ("5) Quit calculator.py")
    print (" ")

    return input ("Choose your option: ")
print (menu())

# this adds two numbers given
def add(a,b):
    print (a, "+", b, "=", a + b)

# this subtracts two numbers given
def sub(a,b):
    print (b, "-", a, "=", b - a)

# this multiplies two numbers given
def mul(a,b):
    print (a, "*", b, "=", a * b)

# this divides two numbers given
def div(a,b):
    print (a, "/", b, "=", a / b)

# NOW THE PROGRAM REALLY STARTS, AS CODE IS RUN
loop = 1
choice = 0


while loop == 1:
    choice = (menu())
    if choice == 1:
        add(input("Add this: "),input("to this: "))
    elif choice == 2:
        sub(input("Subtract this: "),input("from this: "))
    elif choice == 3:
        mul(input("Multiply this: "),input("by this: "))
    elif choice == 4:
        div(input("Divide this: "),input("by this: "))
    elif choice == 5:
    loop = 0

print ("Thankyou for using calculator.py!")

thorbarry

Nice one, thanks alot dude. I'll give it a crack when I'm home

thorbarry

hey tried that and still getting the same issue

can you or anyone advise?

duffman85

http://docs.python.org/3.3/library/functions.html#input

input returns a string not an integer. to see this open a python shell

>>> test=input("Enter a number: ")
Enter a number: 5
>>> test
'5'
>>> if test==5:
	print("test equals five")
else:
	print("test does not equal five")
	print(test.__class__)

	
test does not equal five
<class 'str'> 

A string will never equal a number - so you need to convert it to an integer(int) using the int(x) function

So you could do

return int(input ("Choose your option: "))