Element wise concat with two list of lists in Python

Question

I have 2 list of lists:

a = [['Apple'], ['Banana']]
b = [[1,2,3,4], [4,5,6]]

How can I concatenate as strings element wise and get a new list of lists as below:

new_list = [['Apple1', 'Apple2', 'Apple3', 'Apple4'], ['Banana4', 'Banana5', 'Banana6']]

Best Regards.

Rakesh · Accepted Answer · 2020-01-22 08:07:12Z

4

Using itertools.cycle

Ex:

from itertools import cycle

a = [['Apple'], ['Banana']] 
b = [[1,2,3,4], [4,5,6]]

result = [[m+str(n) for m, n in zip(cycle(i), j) ] for i,j in zip(a, b)]
print(result)

Output:

[['Apple1', 'Apple2', 'Apple3', 'Apple4'], ['Banana4', 'Banana5', 'Banana6']]

answered Jan 22, 2020 at 8:07

Rakesh

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Comments

Chris · Accepted Answer · 2020-01-22 08:28:39Z

2

One without itertools:

[["%s%s" % (i[0], n) for n in j] for i,j in zip(a,b)]

Output:

[['Apple1', 'Apple2', 'Apple3', 'Apple4'], ['Banana4', 'Banana5', 'Banana6']]

answered Jan 22, 2020 at 8:28

Chris

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Comments

user11955706 · Accepted Answer · 2020-01-22 08:29:14Z

1

can this help you?

a = [['Apple'], ['Banana']]
b = [[1,2,3,4], [4,5,6]]
print([
    [c + str(d) for d in j for c in i] for i, j in zip(a, b)
])

Output:

[['Apple1', 'Apple2', 'Apple3', 'Apple4'], ['Banana4', 'Banana5', 'Banana6']]

answered Jan 22, 2020 at 8:29

user11955706

Comments

kederrac · Accepted Answer · 2020-01-22 09:36:45Z

1

you can use 2 for loops:

new_list = []
for [item], numbers in zip(a, b):
    item_list = []
    for n in numbers:
        item_list.append(f'{item}{n}')
    new_list.append(item_list)

new_list

output:

[['Apple1', 'Apple2', 'Apple3', 'Apple4'], ['Banana4', 'Banana5', 'Banana6']]

or you can use list comprehension:

[[f'{item}{n}' for n in numbers] for [item], numbers in zip(a, b)]

answered Jan 22, 2020 at 9:36

kederrac

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