Element-wise Matrix Difference in Python

When it is required to print element wise matrix difference, the list elements are iterated over and the zip method is used on these values.

Example

Below is a demonstration of the same

my_list_1 = [[3, 4, 4], [4, 3, 1], [4, 8, 3]]
my_list_2 = [[5, 4, 7], [9, 7, 5], [4, 8, 4]]
print("The first list is :")
print(my_list_1)
print("The second list is :")
print(my_list_2)

my_result = []

for sub_str_1, sub_str_2 in zip(my_list_1, my_list_2):
   temp_str = []

   for element_1, element_2 in zip(sub_str_1, sub_str_2):
      temp_str.append(element_2-element_1)
   my_result.append(temp_str)

print("The result is :")
print(my_result)

Output

The first list is :
[[3, 4, 4], [4, 3, 1], [4, 8, 3]]
The second list is :
[[5, 4, 7], [9, 7, 5], [4, 8, 4]]
The result is :
[[2, 0, 3], [5, 4, 4], [0, 0, 1]]

Explanation

• Two list of lists are defined and are displayed on the console.

• An empty list is created.

• The two list of lists are zipped, using the zip method and iterated over.

• Inside the ‘for’ loop, an empty list is created, and the elements of the list of lists are appended to the list.

• Outside this, the list is appended to the other list.

• This is displayed as output on the console.