Vfrdtyky

I have created a matrix called rix.

rix = [[1,2,3],[4,5,6][7,8,9]]

And as an input I have variable put which is a single list of length 2 which represents the position of the matrix. The part that I'm struggling in, is how do I check that the variable put represents one of the positions in the first column?

Design your function to be generic; it should take the argument row_n (row number) that represents which row you want to check its bounds. Check if the row_n exists in your rix's list. Then, do a comparison between your put's second element (that represents the expected row length) with the original row_n length in the rix list.

According to your case, you should compare if the put's second element is less than or equal to the rix's row_n length and then return your booleans.

You use len(rix) to evaluate the number of rows
and len(rix[0]) to evaluate the number of columns your matrix has

so

if len(rix) <= put[0]:

    return false

elif len(rix[0]) <= put[1]:

    return false

else:

    return true

You also have to consider negative indices.

def in_first_col(put, list2D):

    row_idx, col_idx = put



    # return False if we can't get the row

    try:

       row = list2D[row_idx]

    except IndexError:

       return False



    # return False if row is empty

    # return False if col_idx does not refer to first element of row

    return row and (col_idx == 0 or col_idx == -len(row))

Demo:

>>> rix = [[1,2,3],[4,5,6],[7,8,9]]

>>> in_first_col([1,1], rix)

>>> False

>>> in_first_col([2,0], rix)

>>> True

>>> in_first_col([5,0], rix)

>>> False

>>> in_first_col([-2,-3], rix)

>>> True