Combine two lists alternatively

Question

I am doing a simple list comprehension: combine two lists in alternative order and make another list.

big_list = [i,j for i,j in zip(['2022-01-01','2022-02-01'],['2022-01-31','2022-02-28'])]

Expected output:

['2022-01-01','2022-01-31','2022-02-01','2022-02-28']

Present output:

Cell In[35], line 1
    [i,j for i,j in zip(['2022-01-01','2022-02-01'],['2022-01-31','2022-02-28'])]
     ^
SyntaxError: did you forget parentheses around the comprehension target?

Answer 1

Do a nested comprehension to pull the items out of the zipped tuples:

big_list = [
    i
    for t in zip(
        ['2022-01-01','2022-02-01'],
        ['2022-01-31','2022-02-28']
    )
    for i in t
]