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I am new to Python and I would like to combine two arrays. I have two arrays: A and B and would like to get array C as follows:

A = [1, 2, 3, 4, 5] 
B = [6, 7, 8, 9, 10]

Result array:

C = [(1, 6), (2, 7), (3, 8), (4, 9), (5, 10)]
Tomerikoo
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Pratheek Hb
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    Usually this operation would not be referred to as "concatenation". The concatenation of `A and B` would be `A + B = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]`. – ApproachingDarknessFish Oct 19 '20 at 07:19
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    I would call this a good question. The problem is simple yes, but judging from the answers the `zip` function is not as widely used as it should be, so the question already had its merit. Additionally, because of the unconventional description of 'concatenation', googling for it would have never yielded the desired results. Furthermore it was well asked, provided a nicely formatted example and described it very well. That is well asked question, especially for a newcommer! Welcome to stackoverflow! – jaaq Oct 19 '20 at 07:27
  • Does this answer your question? [How to iterate through two lists in parallel?](https://stackoverflow.com/questions/1663807/how-to-iterate-through-two-lists-in-parallel) – Tomerikoo Oct 19 '20 at 07:33
  • By the way, these are all lists, not arrays – Tomerikoo Oct 19 '20 at 07:35

2 Answers2

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Use zip, the built-in for pairwise iteration:

C = list(zip(A, B))

Note that you are not concatenating the two lists.

user2390182
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  • Thanks for your solution. But, the following solution resulted in C= [('1', '6'), ('2', '7'), ('3', '8'), ('4', '9'), ('5', '10')] which is not correct. I need C = [(1, 6), (2, 7), (3, 8), (4, 9), (5, 10)] – Pratheek Hb Oct 19 '20 at 07:47
  • @PratheekHb this means you have a list of strings and not ints as you presented in the question... – Tomerikoo Oct 19 '20 at 07:49
  • Then your input was not what you showed in the question, but `['1', '2', '3', '4', '5']`, etc. You can easily fix this: `list(zip(map(int, A), map(int, B)))` – user2390182 Oct 19 '20 at 07:50
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Without any dependency:

>>> A = [1, 2, 3, 4, 5]
>>> B = [6, 7, 8, 9, 10]
>>> C = [(A[i], B[i]) for i in range(len(A))]
>>> C
[(1, 6), (2, 7), (3, 8), (4, 9), (5, 10)]
Tomerikoo
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Blusky
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  • Incorrect. 1. `len(A)` is not an iterable. 2. If you change `len(A)` to `range(len(A))`, this approach will raise an `IndexError` if `len(B) > len(A)`. – ApproachingDarknessFish Oct 19 '20 at 07:16
  • Corrected with range (misread history). The behavior if `len(A) != len(B)` has not been specified, so nothing wrong in that case. – Blusky Oct 19 '20 at 07:19
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    Instructive solution. `zip` is, however, not more of a dependency than `range` or `len`. The are all just built-ins. – user2390182 Oct 19 '20 at 07:27
  • The following solution resulted in C= [('1', '6'), ('2', '7'), ('3', '8'), ('4', '9'), ('5', '10')] which is not correct. I need C = [(1, 6), (2, 7), (3, 8), (4, 9), (5, 10)] – Pratheek Hb Oct 19 '20 at 07:46