Write a recursive function column2list_rec(grid, n), where gridis a list of lists and n is an integer, that returns a list consisting of the element at position n of each row of grid.

You can assume that 0 ? n < len(r) for each row (i.e., element) of grid.

Programming Requirements

Solve this problem using recursion. You are allowed to use onlythe following programming constructs:

if statements;

return statements;

assignment;

recursive function calls (but not to helper functions);

comparison operations (==, !=, etc.);

list indexing and slicing;

list concatenation/extension.

Solutions that go outside these constructs, e.g., by using for/while loops or list comprehensions, will not get credit.