CODEWITHSUNDEEP
pythonlistcode-formatting
Denisuu
Denisuu

Reputation: 43

Adding comma's and and's between lists

How do I add a comma between every list element and an "and" between the last 2 so the output would be:

My cats are: Bella
My cats are: Bella and Tigger
My cats are: Bella, Tigger and Chloe
My cats are: Bella, Tigger, Chloe and Shadow

Here're the two functions I have, both don't work properly:

Example = ['Bella', 'Tigger', 'Chloe', 'Shadow']

def comma_and(list):
    for i in range(len(list)):
        print('My Cats are:',', '.join(list[:i]), 'and', list[-1],)


def commaAnd(list):
    for i in range(len(list)):
        print('My Cats are:',', '.join(list[:i]), list.insert(-1, 'and'))

My current output is:

>> comma_and(Example)
My Cats are:  and Shadow
My Cats are: Bella and Shadow
My Cats are: Bella, Tigger and Shadow
My Cats are: Bella, Tigger, Chloe and Shadow

>> commaAnd(Example)
My Cats are:  None
My Cats are: Bella None
My Cats are: Bella, Tigger None
My Cats are: Bella, Tigger, Chloe None

Upvotes: 1

Views: 2962

Answers (2)

Ishan Anand
Ishan Anand

Reputation: 403

The condition where there is only one cat in the list needs special handling. What I'll do is, first join the elements of list starting from index 0 till second last element with a comma.

', '.join(list[:-1]) does this part. The point worth noting here is if the list has only one cat then list[:-1] will be an empty list and thus ', '.join(list[:-1]) will be an empty string. So, I just took advantage of this empty string in finding out if the list has only one cat.

def comma_and(list):
    cats = ', '.join(list[:-1])
    if cats:
        cats += ' and ' + list[-1]
    else:
        cats = list[0]
    print("My cats are: " + cats)

Upvotes: 1

poke
poke

Reputation: 387607

The first solution is already almost what you want. You just have to make sure that you don’t always take the last element from the list (-1) but the last item from the current iteration:

>>> for i in range(len(list)):
        print('My Cats are:',', '.join(list[:i]), 'and', list[i])

My Cats are:  and Bella
My Cats are: Bella and Tigger
My Cats are: Bella, Tigger and Chloe
My Cats are: Bella, Tigger, Chloe and Shadow

And then you just need to special-case the first iteration when there is only a single item:

>>> for i in range(len(list)):
        if i == 0:
            cats = list[0]
        else:
            cats = ', '.join(list[:i]) + ' and ' + list[i]
        print('My Cats are:', cats)


My Cats are: Bella
My Cats are: Bella and Tigger
My Cats are: Bella, Tigger and Chloe
My Cats are: Bella, Tigger, Chloe and Shadow

Upvotes: 1

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