Automate the boring stuff with Python - Comma Code exercise

PS The book doesn't reach the join function yet so you have to use if,elif and else. Asked the question before but this is only like chapter 2-3 guys, We haven't gotten to use join yet

So in the comma code exercise in automate the boring stuff you have to create a list and print it out using commas between each item and add 'and' before the last item.

Example

spam = ['apples','bana', 'apple']
def commacode(passedlist):
    stringy = ''
    if len(passedlist) == 1:
        stringy += str(passedlist[0])
        return stringy
    for i in range(len(passedlist)-1):
        stringy += str(passedlist[i]) + ', '
        # adds all except last item to str
    stringy += 'and ' + str(passedlist[len(passedlist)-1])
    # adds last item to string, after 'and'
    return stringy
print(commacode(spam)) 

outputs apples , bana, and apple.

However if it is only two items it would print out apples, and bana which isnt grammatically correct. So my question is how would I make it correct I tried adding a elif and else statement but it broke my code and I didn't save it to show you guys(sorry)

It's easiest to handle 1- and 2-length lists as special cases. They're both simple enough that you can take care of them in a single line of code (with no looping involved), and then loop to handle all the remaining cases (which are all done in the same way):

def commacode(words):
    if len(words) == 1:
        return words[0]
    if len(words) == 2:
        return f"{words[0]} and {words[1]}"
    ret = ""
    for word in words[:-1]:
        ret += f"{word}, "
    return ret + f"and {words[-1]}"

print(commacode(["spam"]))  # spam
print(commacode(["spam", "eggs"]))  # spam and eggs
print(commacode(["spam", "eggs", "spam", "spam"]))
# spam, eggs, spam, and spam

An elif, and else statement is what you need, you were on the right track.

spam = ['apples','banana','apple']
def commacode(passedlist):
    stringy = ''
    if len(passedlist) == 1:
        stringy += str(passedlist[0])
        return stringy
    # added the elif here to check if list is only 2 objects
    elif len(passedlist) == 2:
        # this adds the strings together 
        stringy = passedlist[0] + ' and ' + passedlist[1]
    # else statement is required so this code only runs
    # if the list is not of length 1 or 2
    else:
        for i in range(len(passedlist)-1):
            stringy += str(passedlist[i]) + ', '
            # adds all except last item to str
        stringy += 'and ' + str(passedlist[len(passedlist)-1])
        # adds last item to string, after 'and'
    return stringy
print(commacode(spam)) 

You had the right idea with the elif and else statement, I would just imagine that you might have had indentations wrong or something.

spam = ['apples', 'bana', 'apple']

def commacode(passedlist):
    stringy = ''
    for i in range(len(passedlist)):
        if i==len(passedlist)-1 and i>0:
            stringy += " and "
        stringy += passedlist[i]
        if i<len(passedlist)-2:
            stringy+= ", "
    return stringy

print(commacode(spam))