Examples:
Input: arr = [[1, 2, 3], [4, 5, 6], [2, 1, 2]] Output: Sum = 26
This problem can be easily solved using two for loops iterating over the entire matrix, but we can quickly solve this problem in python using the map () function.
# A function to calculate the sum of all elements in a matrix
# sum (arr) is a builtin Python function that calculates
# the sum of each item in the iterable (array, list, etc.).
# map (sum, arr) applies the given function to each item
# iterable and returns a list of results.
def
findSum (arr):
# internal map function applies inline function
# sum on each line arr matrices and returns
# list of sum of elements of each row
return
sum
(
map
(
sum
, arr))
# Driver function
if
__ name__
=
=
" __ main__ "
:
arr
=
[[
1
,
2
,
3
], [
4
,
5
,
6
], [
2
,
1
,
2
]]
print
"Sum ="
, findSum (arr)
Output:
26
What does map () do?
The map () function applies the given function to each element of the iterable (list , tuple, etc.) and returns a list of results. For example, see the example below:

Output:
[1 , 4, 9, 16]
This article courtesy of Shashankom Mishra (Gullu) . If you are as Python.Engineering and would like to contribute, you can also write an article using contribute.python.engineering or by posting an article contribute @ python.engineering. See my article appearing on the Python.Engineering homepage and help other geeks.
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