Question

This is code is an from a lesson i’m doing in class at school and i’m confused about how the list gets printed because it keeps ending with “None”…

def printlist(myList, pointer):
    print("The List is: ", myList)
    print("Pointer length: ", pointer)
    print("The List length is: ", len(myList))
    print("The List printed properly:")
    print(printlistproperly(myList))

def printlistproperly(myList):
    thelength = len(myList)
    for i in range(thelength):
        print(i, " ", myList[i])

def popin(myList,pointer):
    myList.append(input("Enter a value: "))
    pointer = len(myList)-1
    return myList, pointer

def main():
    myList = ["Ford","Toyota","Mustang"]
    pointer = len(myList)-1
    myList,pointer = popin(myList,pointer)
    printlist(myList, pointer)

The results are:

>>> main()
Enter a value: Dodge
The List is:  ['Ford', 'Toyota', 'Mustang', 'Dodge']
Pointer length:  3
The List length is:  4
The List printed properly:
0   Ford
1   Toyota
2   Mustang
3   Dodge
None

My real problem is… What’s the None at the end?? Where does it come from? How can I fix it?

Answer 1

In the function printlist you print the result of the function printlistproperly, which returns nothing. Therefore you get the None. Solution: Just call printlistproperly(myList) (without the print).

def printlist(myList, pointer):
    print("The List is: ", myList)
    print("Pointer length: ", pointer)
    print("The List length is: ", len(myList))
    print("The List printed properly:")
    printlistproperly(myList)