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

Python Lambda: Exercise-30 with Solution

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 :

def sort_matrix(M):
    result = sorted(M, key=lambda matrix_row: sum(matrix_row)) 
    return result

matrix1 = [[1, 2, 3], [2, 4, 5], [1, 1, 1]]
matrix2 = [[1, 2, 3], [-2, 4, -5], [1, -1, 1]]

print("Original Matrix:")
print(matrix1)
print("\nSort the said matrix in ascending order according to the sum of its rows") 
print(sort_matrix(matrix1))
print("\nOriginal Matrix:")
print(matrix2) 
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]]

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Python: Tips of the Day

Inverts a dictionary with non-unique hashable values:

Example:

def tips_collect_dictionary(obj):
  inv_obj = {}
  for key, value in obj.items():
    inv_obj.setdefault(value, list()).append(key)
  return inv_obj
ages = {
  "Owen": 25,
  "Jhon": 25,
  "Pepe": 15,
}
print(tips_collect_dictionary(ages))

Output:

{25: ['Owen', 'Jhon'], 15: ['Pepe']}