How do I get my variables from one function to another?

Question

def getInt():
    while True:
        width = int(input("Enter width (1 - 60):"))
        if width > 1 and width < 60:
            break
        else:
            print("Please enter a valid input")
    while True:
        height = int(input("Enter width (1 - 20):"))
        if height > 1 and height < 20:
            break
        else:
            print("Please enter a valid input")
    return width, height


def calcPerimeter(width, height):
    perimeter = (2 * (width + height))
    return perimeter  

def calcArea(width, height):
    area = width * height
    return area


def main():
print('Results: {}'.format(getInt()))
print('The perimeter is {}' .format(calcPerimeter(width, height)))
print('The area is {}' .format(calcArea(width, height)))


main()

When I run, it says:

Traceback (most recent call last):

main()

print('The perimeter is {}' .format(calcPerimeter(width, height)))

NameError: name 'width' is not defined

Do you know `variable scopes`? Do you think `width` is visible in `main` method? — sagarr, Oct 02 '17 at 05:01
`getInt()` returns width and height, but when you call `getInt()`, you aren't saving the returned values anywhere. Try this: `width, height = getInt()`. — John Gordon, Oct 02 '17 at 05:01
If i print the values in getInt i get them back as the values, i just cant get them into the other functions. — Joey Swartz, Oct 02 '17 at 05:02

score 2 · Answer 1 · answered Oct 02 '17 at 05:03

maybe you can try changing your main() into this

def main():
  width, height = getInt()
  print('Results: {}, {}'.format(width, height))  
  print('The perimeter is {}' .format(calcPerimeter(width, height)))
  print('The area is {}' .format(calcArea(width, height)))

you need to return getInt() to specific variable, before passing into another function

the other ways is calling calculatePerimeter and calculateArea inside the getInt() function, here is the example

def getInt():
    while True:
        width = int(input("Enter width (1 - 60):"))
        if width > 1 and width < 60:
            break
        else:
            print("Please enter a valid input")
    while True:
        height = int(input("Enter width (1 - 20):"))
        if height > 1 and height < 20:
        break
        else:
            print("Please enter a valid input")
    return calcPerimeter(width, height), calcArea(width, height)


def calcPerimeter(width, height):
    perimeter = (2 * (width + height))
    return perimeter  

def calcArea(width, height):
    area = width * height
    return area


def main():
  perimeter, area = getInt()
  print('Perimeter is {}, area is {}'.format(perimeter, area))  


main()

score 0 · Answer 2 · answered Oct 02 '17 at 05:03

0

One way is to use Global Keyword. another way is to return the required variables from the function and saving them in the global scope.

answered Oct 02 '17 at 05:03

Max

1,283
9
20

score 0 · Answer 3 · answered Oct 02 '17 at 05:08

0

You should read this post and in general study the rules of variable scopes. As a programmer this is essential knowledge.

Short Description of the Scoping Rules?

answered Oct 02 '17 at 05:08

Orpedo

483
5
14

score 0 · Answer 4 · answered Oct 02 '17 at 05:10

Refer this (link)[http://python-textbok.readthedocs.io/en/1.0/Variables_and_Scope.html] to understand why changing your main function to Po's answer makes the code run correctly.

The variables defined inside the functions calcPerimeter and calcArea are not visible/accessible to the main function because of being in a different scope.

score 0 · Answer 5 · answered Oct 02 '17 at 06:04

#I think i have resolved your problem.In your case it was returning list/tuple .you have to convert it into simple variable
def getInt():
  while True:
     width = int(input("Enter width (1 - 60):"))
     if width > 1 and width < 60:
        break
     else:
        print("Please enter a valid input")
while True:
    height = int(input("Enter height (1 - 20):"))
    if height > 1 and height < 20:
        break
    else:
        print("Please enter a valid input")
return width,height


 def calcPerimeter(width, height):
   hw=width+height
   perimeter = 2*hw
   return perimeter  

def main():
  width,height= getInt()
  p=calcPerimeter(width, height)
  print('The perimeter is %s'%p)
  a=calcArea(width, height)
  print('The area is %s'%a)


main()

How do I get my variables from one function to another?

5 Answers5