In the previous article, we have discussed Python Program to Display an Upper Triangular Matrix
Given a matrix and the task is to find the sum of all elements in a 2-dimensional array of the given matrix in Python.
What is a matrix:
A matrix is a rectangular sequence of numbers divided into columns and rows. A matrix element or entry is a number that appears in a matrix.
Example:
Above is the matrix which contains 5 rows and 4 columns and having elements from 1 to 20.
In this order, the dimensions of a matrix indicate the number of rows and columns.
Here as there are 5 rows and 4 columns it is called a 5*4 matrix.
Examples:
Example1:
Input:
Given Matix : 1 6 4 8 1 3 1 6 2
Output:
The sum of all elements in 2 dimensional array for a given matrix is : 32
Example2:
Input:
Given Matix : 0 8 3 7
Output:
The sum of all elements in 2 dimensional array for a given matrix is : 18
Program to Find the Sum of all Elements in a 2D Array in Python
Below are the ways to find the sum of all elements in a 2-dimensional array of the given matrix in Python:
Method #1: Using For Loop (Static Input)
Approach:
- Give the matrix as static input and store it in a variable.
- Calculate the number of rows of the given matrix by calculating the length of the nested list using the len() function and store it in a variable mtrxrows.
- Calculate the number of columns of the given matrix by calculating the length of the first list in the nested list using the len() function and store it in a variable mtrxcolums.
- Take a variable say rslt_sum and initialize its value to 0.
- Loop till the given number of rows using the For loop.
- Inside the For loop, Iterate till the given number of columns using another Nested For loop(Inner For loop).
- Add the gvnmatrix[n][m] to the above-initialized rslt_sum and store it in the same variable rslt_sum.
- Print the variable rslt_sum to get the sum of all elements in a 2-dimensional array for a given matrix.
- The Exit of the Program.
Below is the implementation:
# Give the matrix as static input and store it in a variable. mtrx = [[1, 6, 4], [8, 1, 3], [1, 6, 2]] # Calculate the number of rows of the given matrix by # calculating the length of the nested list using the len() function # and store it in a variable mtrxrows. mtrxrows = len(mtrx) # Calculate the number of columns of the given matrix by # calculating the length of the first list in the nested list # using the len() function and store it in a variable mtrxcols. mtrxcols = len(mtrx[0]) print("The sum of all elements in 2 dimensional array for a given matrix is :") # Take a variable say rslt_sum and initialize its value to 0. rslt_sum = 0 # Loop till the given number of rows using the For loop. for n in range(mtrxrows): # Inside the For loop, Iterate till the given number of columns using another # Nested For loop(Inner For loop). for m in range(mtrxcols): # Add the gvnmatrix[n][m] to the above-initialized # rslt_sum and store it in the same variable rslt_sum. rslt_sum += mtrx[n][m] # Print the variable rslt_sum to get the sum of all elements in a 2 dimensional array for # a given matrix print(rslt_sum)
Output:
The sum of all elements in 2 dimensional array for a given matrix is : 32
Method #2: Using For loop (User Input)
Approach:
- Give the number of rows of the matrix as user input using the int(input()) function and store it in a variable.
- Give the number of columns of the matrix as user input using the int(input()) function and store it in another variable.
- Take a list and initialize it with an empty value using [] or list() to say gvnmatrix.
- Loop till the given number of rows using the For loop
- Inside the For loop, Give all the row elements of the given Matrix as a list using the list(),map(),int(),split() functions and store it in a variable.
- Add the above row elements list to gvnmatrix using the append() function.
- Take a variable say rslt_sum and initialize its value to 0.
- Loop till the given number of rows using the For loop.
- Inside the For loop, Iterate till the given number of columns using another Nested For loop(Inner For loop).
- Add the gvnmatrix[n][m] to the above-initialized rslt_sum and store it in the same variable rslt_sum.
- Print the variable rslt_sum to get the sum of all elements in a 2-dimensional array for a given matrix.
- The Exit of the Program.
Below is the implementation:
# Give the number of rows of the matrix as user input using the int(input()) function # and store it in a variable. mtrxrows = int(input('Enter some random number of rows of the matrix = ')) # Give the number of columns of the matrix as user input using the int(input()) function # and store it in another variable. mtrxcols = int(input('Enter some random number of columns of the matrix = ')) # Take a list and initialize it with an empty value using [] or list() to say gvnmatrix. mtrx = [] # Loop till the given number of rows using the For loop for n in range(mtrxrows): # Inside the For loop, Give all the row elements of the given Matrix as a list using # the list(),map(),int(),split() functions and store it in a variable. l = list(map(int, input( 'Enter {'+str(mtrxcols)+'} elements of row {'+str(n+1)+'} separated by spaces = ').split())) # Add the above row elements list to gvnmatrix using the append() function. mtrx.append(l) print("The sum of all elements in 2 dimensional array for a given matrix is :") # Take a variable say rslt_sum and initialize its value to 0. rslt_sum = 0 # Loop till the given number of rows using the For loop. for n in range(mtrxrows): # Inside the For loop, Iterate till the given number of columns using another # Nested For loop(Inner For loop). for m in range(mtrxcols): # Add the gvnmatrix[n][m] to the above-initialized # rslt_sum and store it in the same variable rslt_sum. rslt_sum += mtrx[n][m] # Print the variable rslt_sum to get the sum of all elements in a 2 dimensional array for # a given matrix print(rslt_sum)
Output:
Enter some random number of rows of the matrix = 2 Enter some random number of columns of the matrix = 2 Enter {2} elements of row {1} separated by spaces = 0 8 Enter {2} elements of row {2} separated by spaces = 3 7 The sum of all elements in 2 dimensional array for a given matrix is : 18
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