Activity 27

Two dimensional lists are a very common data structure when dealing with large data. For example, images can be thought of as a two-dimensional list of pixels. They can be a little confusing when using them the first time. Perform the following exercises to solidify your understanding of 2-D lists.

For each of the following, what would the program print if run? Assume that the variable my_matrix is defined as follows

[['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i']]

1. print(my_matrix[2])
   

2. print(my_matrix[1][0])
   

3. for element in my_matrix[2]:
       print(element)
   

4. for i in range(len(my_matrix)):
       print(my_matrix[i][0])
   

5. for i in range(len(my_matrix)):
       print(my_matrix[i][-i - 1])
   

6. my_matrix[1].append("j")
   print(my_matrix)  
   

7. Assume this is executed after the previous sample.

   for row in my_matrix:
      for col in row:
         print(col, end=" ")
      print()