How do I make independent lists within in a list?

user_13032963 0
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seats = 4  # user can choose an even input, I put 4 for this example
rows = 4  # user can choose an even or odd input, I put 4 for this example
seats_in_row_list = [i for i in string.ascii_uppercase[:seats]]
main_seat_list = [seats_in_row_list for i in range(rows)]

The output is:

[['A', 'B', 'C', 'D'], ['A', 'B', 'C', 'D'], ['A', 'B', 'C', 'D'], ['A', 'B', 'C', 'D']]

But when I try to change 'A' to 'X' in the first list all of the lists change:

[['X', 'B', 'C', 'D'], ['X', 'B', 'C', 'D'], ['X', 'B', 'C', 'D'], ['X', 'B', 'C', 'D']]

What I'm looking for is this output:

[['X', 'B', 'C', 'D'], ['A', 'B', 'C', 'D'], ['A', 'B', 'C', 'D'], ['A', 'B', 'C', 'D']]
list python
2 Answers

Use copy method to have a copy of the individual list before assigning

main_seat_list = [seats_in_row_list.copy() for i in range(rows)]
user_48403380

If you aren't using seats_in_row_list for anything other than the construction of main_seat_list, you should just inline the definition. Calling list here would be simpler than using a list comprehension.

seats = 4
rows = 4
main_seat_list = [list(string.ascii_uppercase[:seats]) for i in range(rows)]
user_11268410
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