Creating one nested list from separate lists

Question

Say I have the following lists:

list_1 = [1, 2, 3]
list_2 = ['a', 'b', 'c']
list_3 = ['red', 'yellow', 'blue']

And I want to create one list of lists, as follows:

combined_list = [[1, 'a', 'red'],
                 [2, 'b', 'yellow'],
                 [3, 'c', 'blue']]

What is the best way of going about this?

Does this answer your question? [Matrix Transpose in Python](https://stackoverflow.com/questions/4937491/matrix-transpose-in-python) — AMC, Feb 27 '20 at 02:11
It's not an **exact** duplicate but it's incredibly close, and the core of the solution (`zip()`) is what matters. — AMC, Feb 27 '20 at 02:12

kebab-case · Answer 1 · 2020-02-26T21:59:03.007

2

Just use zip. You will need to cast each produced tuple into a list and use a list comprehension as the following example:

combined_list = [list(tuple) for tuple in zip(list_1, list_2, list_3)]

edited Feb 26 '20 at 21:59

answered Feb 26 '20 at 21:51

kebab-case

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Александр · Answer 2 · 2020-02-26T21:57:10.920

1

list_1 = [1, 2, 3] 
list_2 = ['a', 'b', 'c'] 
list_3 = ['red', 'yellow', 'blue']

combined_list = []
combined_list+=map(list, zip(list_1, list_2, list_3))
print(combined_list)

Result:

[[1, 'a', 'red'], [2, 'b', 'yellow'], [3, 'c', 'blue']]

edited Feb 26 '20 at 21:57

answered Feb 26 '20 at 21:52

Александр

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11

This is just going to create a list of lists, without mixing elements in the way OP is asking for. – kebab-case Feb 26 '20 at 21:54
@Minyc510 , yes, you are right. I wrongly read the task first. But already corrected the answer – Александр Feb 26 '20 at 22:07

score 0 · Answer 3 · answered Feb 26 '20 at 21:55

ASSUMPTIONS:

All your lists list_1,list_2 and list_3 are of equal length

Solution

You simply iterate through the list and append the combined list for each index to an an empty list

def combine(l1,l2,l3):
    res = []
    for i in range(len(l1)):
        res.append([l1[i],l2[i],l3[i]])
    return res

Now you can simply call this function with your lists list_1, list_2 and list_3 like this

combined = combine(list_1,list_2,list_3)

Creating one nested list from separate lists

3 Answers3

ASSUMPTIONS:

Solution