Automate the boring stuff pratice project: Comma Code. A function that takes a list value as an argument and returns a string with all the items seperated by a comma and a space, with 'and' inserted before the last item.

commaCode.py

# lists to test
foo = ['apples', 'bananas', 'tofu', 'cats']
a = ['bat', 'rat', 'elephant', 'snake', 'hippo']
b = ['Ben', 'Ryan', 'Arthur', 'Dillon', 'Andre', 'Agnes', 'Aaron']
d = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'] 

# comma code function
def commaCode(myList):
    s = '' # creates an empty string vector
    last = myList[len(myList) - 1] # gets the last value from the list
    length = int(len(myList)) - 1 # gets the length of the list
    newList = myList[0:length] # creates a new list without the last value from the list
    for words in newList:
        s += words + ', ' # putting the values from the list as a string seperated by commas
    print(s + ' and ' + last) # prints the final string with the last value added to it

commaCode(foo)
commaCode(a)
commaCode(b)
commaCode(d)

spam = ['appeles','bananas','tofu','cats']
spam.insert(-1,'and')
for i in range(len(spam)-2):
print("'" + spam[i],end=',')
print(spam[-2] + ' ' + spam[-1] +"'" + '.')

I really like your solution of creating a new list! Short and clean code. I think your solution would go out of range for an empty list though? And if you have only 1 value in the list, it will still print a comma. I added my code below in replit link where I take care of this with some simple if statements. I could clean my code up a bit by using your newList method!
https://replit.com/@DOdrums/commaCode#main.py

def comma_code(lst):

    """Write a function that takes a list value as an argument and returns
    a string with all the items separated by a comma and a space, with and
    inserted before the last item."""

    new_string = ''

    for idx, item in enumerate(lst):

        # Special cases
        if len(lst) == 0:
            return None
        if len(lst) == 1:
            return item

        # General solution
        if idx == len(lst) - 1:
            new_string += f"and {item}"
            return new_string
        new_string += item + ', '

def comma_code(words): if len(words) == 1: return words[0] return '{}, and {}'.format(', '.join(words[:-1]), words[-1])

# lists to test
foo = ['apples', 'bananas', 'tofu', 'cats']
a = ['bat', 'rat', 'elephant', 'snake', 'hippo']
b = ['Ben', 'Ryan', 'Arthur', 'Dillon', 'Andre', 'Agnes', 'Aaron']
d = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'] 

# comma code function
def commaCode(myList):
    s = '' # creates an empty string vector
    last = myList[len(myList) - 1] # gets the last value from the list
    length = int(len(myList)) - 1 # gets the length of the list
    newList = myList[0:length] # creates a new list without the last value from the list
    for words in newList:
        s += words + ', ' # putting the values from the list as a string seperated by commas
    print(s + 'and ' + last) # prints the final string with the last value added to it
                             # removed the extra space in ' and ', now displays correctly

commaCode(foo)
commaCode(a)
commaCode(b)
commaCode(d)