Python: Sort a given matrix in ascending order according to the sum of its rows using lambda

Last update on March 28 2025 13:00:08 (UTC/GMT +8 hours)

30. Matrix Row Sum Sort Lambda

Write a Python program to sort a given matrix in ascending order according to the sum of its rows using lambda.

Sample Solution:

Python Code :

# Define a function 'sort_matrix' that takes a matrix 'M' (list of lists) as input
def sort_matrix(M):
    # Sort the matrix 'M' based on the sum of elements in each row using the 'sorted' function
    # The 'key' parameter uses a lambda function to calculate the sum of each matrix row
    result = sorted(M, key=lambda matrix_row: sum(matrix_row)) 
    
    # Return the sorted matrix
    return result

# Define two matrices 'matrix1' and 'matrix2' as lists of lists
matrix1 = [[1, 2, 3], [2, 4, 5], [1, 1, 1]]
matrix2 = [[1, 2, 3], [-2, 4, -5], [1, -1, 1]]

# Print the original matrix 'matrix1'
print("Original Matrix:")
print(matrix1)

# Sort matrix1 based on the sum of its rows and print the sorted result
print("\nSort the said matrix in ascending order according to the sum of its rows") 
print(sort_matrix(matrix1))

# Print the original matrix 'matrix2'
print("\nOriginal Matrix:")
print(matrix2) 

# Sort matrix2 based on the sum of its rows and print the sorted result
print("\nSort the said matrix in ascending order according to the sum of its rows") 
print(sort_matrix(matrix2)) 

Sample Output:

Original Matrix:
[[1, 2, 3], [2, 4, 5], [1, 1, 1]]

Sort the said matrix in ascending order according to the sum of its rows
[[1, 1, 1], [1, 2, 3], [2, 4, 5]]

Original Matrix:
[[1, 2, 3], [-2, 4, -5], [1, -1, 1]]

Sort the said matrix in ascending order according to the sum of its rows
[[-2, 4, -5], [1, -1, 1], [1, 2, 3]]

For more Practice: Solve these Related Problems:

• Write a Python program to sort a matrix in descending order according to the product of its rows using lambda.
• Write a Python program to sort a matrix based on the maximum element in each row using lambda.
• Write a Python program to sort a matrix based on the difference between the first and last elements of each row using lambda.
• Write a Python program to sort a matrix by the average of its rows in descending order using lambda.

Python Code Editor:

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