Create a dictionary by zipping together two lists of uneven length

Question

I have two lists different lengths, L1 and L2. L1 is longer than L2. I would like to get a dictionary with members of L1 as keys and members of L2 as values.

As soon as all the members of L2 are used up. I would like to start over and begin again with L2[0].

L1 = ['A', 'B', 'C', 'D', 'E']    
L2 = ['1', '2', '3']    
D = dict(zip(L1, L2))    
print(D)

As expected, the output is this:

{'A': '1', 'B': '2', 'C': '3'}

What I would like to achieve is the following:

{'A': '1', 'B': '2', 'C': '3', 'D': '1', 'E': '2'}

Answer 1

Use itertools.cycle to cycle around to the beginning of L2:

from itertools import cycle
dict(zip(L1, cycle(L2)))
# {'A': '1', 'B': '2', 'C': '3', 'D': '1', 'E': '2'}

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In your case, concatenating L2 with itself also works.

# dict(zip(L1, L2 * 2))
dict(zip(L1, L2 + L2))
# {'A': '1', 'B': '2', 'C': '3', 'D': '1', 'E': '2'}