Question

0. Python code: using only len(), range(), append(), and del keyword when needed as the directions state? No list comprehension, slicing, or importing modules. Please and thank you.

1. def diagonal_matrix(mat)

   • Converts a square matrix mat into a lower diagonal matrix https://en.wikipedia.org/wiki/Triangular_matrix

   • After the conversion the values on the diagonal will be the sum of the deleted elements in the respective row

   • Return value is None. Variable mat is directly modi ed in memory

   • mat is a nested list (e.g. [[1,2,3], [4,5,6], [7,8,9]] and is guaranteed to have a square

     shape of size at least 2x2

   • You’re not allowed to use slicing, or import modules, or use the list comprehension syntax

   • The only functions you’re allowed to use are: len() , range() and the del keyword

   • Examples:

     ◦ diagonal_matrix([[1,2,3], [4,5,6], [7,8,9]]) → [[6], [4, 11], [7, 8, 9]]

   • ◦ diagonal_matrix([[1,2],[3,4]]) → [[3], [3,4]]

Answer 1

OUTPUT :

CODE :

def diagonal_matrix(mat):
    #Initialize ans
    ans = []
    #Iterate through all arrays in 2d matrix
    for i in range(len(mat)):
        #Initialize array
        f = []
        #take first i elements
        f.extend(mat[i][0:i])
        #Find sum from i+1th element
        f.append(sum(mat[i][i:]))
        ans.append(f)
    return ans