In Python how can I reformat list of words with correct commas and the word "and"?

Question

A student asked for assistance with a Python assignment. She was provided with four lists:

animalList1 = ['dog', 'cat', 'bird', 'tiger', 'lion', 'camel']

animalList2 = ['elephant', 'alligator']

animalList3 = ['horse']

animalList4 = []

The assignment was to create a function that would produce the following output from these or similar lists:

animalList1 - dog, cat, bird, tiger, lion, and camel

animalList2 - elephant and alligator

animalList3 - horse

animalList4 -

Answer 1

As is the case with a lot of simple programming tasks, there are many ways to do this. I eventually settled on this solution:

#Initial variables

animalList1 = ['dog', 'cat', 'bird', 'tiger', 'lion', 'camel']

animalList2 = ['elephant', 'alligator']

animalList3 = ['horse']

animalList4 = []

def commaCode(someList):

newList = [] #create a new, empty list

for i, x in enumerate(someList):

#Count how many words remain (less the current one)

wordsRemaining = len(someList) -1 - i

#Add a comma if there were more than 2 items, and we aren't on the last one

#Hello, Oxford comma.

if wordsRemaining >= 1 and len(someList) != 2:

x += ","

newList.append(x) #Add this word to the new list

#If there is only one word left, add "and" to our list of words

if wordsRemaining == 1:

newList.append("and")

return " ".join(newList) #return a space-joined list of the reformatted words

#Generates the output

for j in range(1,5):

print("animalList" + str(j) + " - " + commaCode(eval("animalList" + str(j))))

The tricky part was getting the correct number of spaces between words.

It seems to work well feel free to post your ideas, below.