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How to merge lists into a list of tuples?

Posted by: admin January 29, 2018 Leave a comment

Questions:

What is the Pythonic approach to achieve the following?

# Original lists:

list_a = [1, 2, 3, 4]
list_b = [5, 6, 7, 8]

# List of tuples from 'list_a' and 'list_b':

list_c = [(1,5), (2,6), (3,7), (4,8)]

Each member of list_c is a tuple, whose first member is from list_a and the second is from list_b.

Answers:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> zip(list_a, list_b)
[(1, 5), (2, 6), (3, 7), (4, 8)]

Questions:
Answers:

In python 3.0 zip returns a zip object. You can get a list out of it by calling list(zip(a, b)).

Questions:
Answers:

Youre looking for the builtin function zip.

Questions:
Answers:

You can use map lambda

a = [2,3,4]
b = [5,6,7]
c = map(lambda x,y:(x,y),a,b)

This will also work if there lengths of original lists do not match

Questions:
Answers:

I know this is an old question and was already answered, but for some reason, I still wanna post this alternative solution. I know it’s easy to just find out which built-in function does the “magic” you need, but it doesn’t hurt to know you can do it by yourself.

>>> list_1 = ['Ace', 'King']
>>> list_2 = ['Spades', 'Clubs', 'Diamonds']
>>> deck = []
>>> for i in range(max((len(list_1),len(list_2)))):
        while True:
            try:
                card = (list_1[i],list_2[i])
            except IndexError:
                if len(list_1)>len(list_2):
                    list_2.append('')
                    card = (list_1[i],list_2[i])
                elif len(list_1)<len(list_2):
                    list_1.append('')
                    card = (list_1[i], list_2[i])
                continue
            deck.append(card)
            break
>>>
>>> #and the result should be:
>>> print deck
>>> [('Ace', 'Spades'), ('King', 'Clubs'), ('', 'Diamonds')]

Questions:
Answers:

The output which you showed in problem statement is not the tuple but list

list_c = [(1,5), (2,6), (3,7), (4,8)]

check for

type(list_c)

considering you want the result as tuple out of list_a and list_b, do

tuple(zip(list_a,list_b))