why list comprehension could select columns of a matrix? : Why the list comprehension could select the columns of a matrix? I am a bit confused by the for loop.

    m=[[1,2,3],[4,5,6],[7,8,9]]
    col=[x for x in m]
    col2=col[1]
    col2
    [4, 5, 6]
    

Obivious the **below** codes give the right answer, but **why is that**? Because in each iteration, the `for loop` takes in a whole instead of a number?

    m=[[1,2,3],[4,5,6],[7,8,9]]
    col2=[x[1] for x in m
    col2
    [2, 5, 8]]