Is possible to eliminate a column of a list of lists if some value is present-CodePudding

I am having a problem with list of lists. I want to know if there is a way to eliminate a column if some value is present Example:

List = [[1, 4, 1, 1, 1, 4, 1],
        [2, 2, 2, 4, 2, 2, 2],
        [3, 3, 3, 3, 3, 3, 3]]

if the number 4 is present in the list of lists eliminate that column giving for result:

Result_List = [[1, 0, 1, 0, 1, 0, 1],
               [2, 0, 2, 0, 2, 0, 2],
               [3, 0, 3, 0, 3, 0, 3]]

Due to 4 is present in List[0][1],List[1][3],List[0][5] Thanks for all the help.

CodePudding user response：

Try:

lst = [[1, 4, 1, 1, 1, 4, 1], 
       [2, 2, 2, 4, 2, 2, 2], 
       [3, 3, 3, 3, 3, 3, 3]]

out = list(
    map(
        list,
        zip(
            *(
                [0] * len(lst) if any(v == 4 for v in c) else c
                for c in zip(*lst)
            )
        ),
    )
)
print(out)

Prints:

[[1, 0, 1, 0, 1, 0, 1], 
 [2, 0, 2, 0, 2, 0, 2], 
 [3, 0, 3, 0, 3, 0, 3]]

CodePudding user response：

First transpose your list with zip and * so it becomes a list of columns:

>>> my_list = [[1, 4, 1, 1, 1, 4, 1],
...         [2, 2, 2, 4, 2, 2, 2],
...         [3, 3, 3, 3, 3, 3, 3]]
>>> [z for z in zip(*my_list)]
[(1, 2, 3), (4, 2, 3), (1, 2, 3), (1, 4, 3), (1, 2, 3), (4, 2, 3), (1, 2, 3)]

Then you can replace columns containing 4 with 0s:

>>> [[0 for _ in z] if 4 in z else z for z in zip(*my_list)]
[(1, 2, 3), [0, 0, 0], (1, 2, 3), [0, 0, 0], (1, 2, 3), [0, 0, 0], (1, 2, 3)]

and then transpose it back using the same zip(*(...)) trick:

>>> [list(z) for z in zip(*([0 for _ in z] if 4 in z else z for z in zip(*my_list)))]
[[1, 0, 1, 0, 1, 0, 1], [2, 0, 2, 0, 2, 0, 2], [3, 0, 3, 0, 3, 0, 3]]