my_list = [[45, 67, 85, 42, 11], [78, 99, 10, 13, 0], [91, 23, 23, 64, 23], [91, 11, 22, 14, 35]]

print("The list is :")
print(my_list)

my_result = []

for index, element in enumerate(my_list):
   my_result.append([ele for index_1, ele in enumerate(element) if index_1 != index])

print("The resultant matrix is :")
print(my_result)

The list is :
[[45, 67, 85, 42, 11], [78, 99, 10, 13, 0], [91, 23, 23, 64, 23], [91, 11, 22, 14, 35]]
The resultant matrix is :
[[67, 85, 42, 11], [78, 10, 13, 0], [91, 23, 64, 23], [91, 11, 22, 35]]