Purpose: to program the calculation of the sum of two matrices, and then print it out in Python.
Examples:
Input: X = [[1,2,3], [4, 5,6], [7, 8,9]] Y = [[9,8, 7], [6,5,4], [3,2,1]] Output: result = [[10,10,10], [10,10,10], [10,10,10]]
We can add a matrix in Python in the following ways.
- Using for loop :
# Program for adding two matrices using a nested loop
X
=
[[
1
,
2
,
3
],
[
4
,
5
,
6
],
[
7
,
8
,
9
]]
Y
=
[[[
9
,
8
,
7
],
[
6
,
5
,
4
],
[
3
,
2
,
1
]]
result
=
[[
0
,
0
,
0
],
[
0
,
0
,
0
],
[
0
,
0
,
0
]]
# iterate over lines
for
i
in
range
(
len
(X)):
# iterate over columns
for
j
in
range
(
len
(X [
0
])):
result [i] [ j]
=
X [i] [j]
+
Y [i] [j]
for
r
in
result:
print
(r)
Output:
[10, 10, 10] [10, 10, 10] [10, 10, 10]
Explanation: —
In this program, we used nested for loops to iterate over every row and every column. At each point, we add the corresponding elements to two matrices and store them as a result. - Usage understanding a nested
# Program for adding two matrices
# using comprehension list
X
=
[[
1
,
2
,
3
],
[
4
,
5
,
6
],
[
7
,
8
,
9
]]
Y
=
[[
9
,
8
,
7
],
[
6
,
5
,
4
],
[
3
,
2
,
1
]]
result
=
[[X [i] [j]
+
Y [i] [j]
for
j
in
range
(
len
(X [
0
]))]
for
i
in
range
(
len
(X))]
for
r
in
result:
print
(r)
Output:
[ 10, 10, 10] [10, 10, 10] [10, 10, 10]
Explanation: —
The output of this program is the same, as stated above. We used nested list comprehension to iterate over each element in the matrix. Understanding lists allows us to write concise codes, and we should try to use them often in Python. They are very useful. - Using
# Program for adding two matrices
# using zip ()
X
=
[[
1
,
2
,
3
],
[
4
,
5
,
6
],
[
7
,
8
,
9
]]
Y
=
[[
9
,
8
,
7
],
[
6
,
5
,
4
],
[
3
,
2
,
1
]]
result
=
[
map
(
sum
,
zip
(
*
t))
for
t
in
zip
(X, Y)]
print
(result)
Output:
[[10, 10, 10], [10, 10, 10 ], [10, 10, 10]]
Explanation: —
The zip function takes an iterator i of each element (list) of the matrix, displays them, adds them with sum () and stores them in map form.
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