Multi dimensional LIST in Python

Though Numpy library or Pandas DataFrame is preferred for matrix handling but still we can use multidimensional lists in python for many requirements.
Creating two dimensional list
my_list=[[1, 0, 0, 4, 6], [3, 9, 8, 0, 0], [3, 9, 1, 1, 5], [0, 9, 3, 0, 8], [8, 6, 1, 9, 7]]
Displaying all elements as matrix
my_list=[[1, 0, 0, 4, 6], [3, 9, 8, 0, 0], [3, 9, 1, 1, 5], [0, 9, 3, 0, 8], [8, 6, 1, 9, 7]]
for i in my_list:
    print(i)
Output
[1, 0, 0, 4, 6]
[3, 9, 8, 0, 0]
[3, 9, 1, 1, 5]
[0, 9, 3, 0, 8]
[8, 6, 1, 9, 7]
Displaying elements
print(my_list[3][4]) # 8
Displaying a row of data , 0th row is first row , so this will display the 3rd row from top.
print(my_list[2]) # [3, 9, 1, 1, 5]
Displaying column ( 2nd column , first column is 0th column )
for x in my_list: 
#    print(x[3])
Or we can also write like this.
[x[3] for x in my_list]
Output
[4, 0, 1, 0, 9]

Deleting rows and columns

Delete 2nd row
my_list=[[1, 0, 0, 4, 6], [3, 9, 8, 0, 0], [3, 9, 1, 1, 5], [0, 9, 3, 0, 8], [8, 6, 1, 9, 7]]
my_list.pop(2) # delete 2nd row , First row is 0th row
print(my_list)
Output
[[1, 0, 0, 4, 6], [3, 9, 8, 0, 0], [0, 9, 3, 0, 8], [8, 6, 1, 9, 7]]
Delete column
my_list=[[1, 0, 0, 4, 6], [3, 9, 8, 0, 0], [3, 9, 1, 1, 5], [0, 9, 3, 0, 8], [8, 6, 1, 9, 7]]
[x.pop(3) for x in my_list] # delete 3rd column, 
print(my_list)
Output
[[1, 0, 0, 6], [3, 9, 8, 0], [3, 9, 1, 5], [0, 9, 3, 8], [8, 6, 1, 7]]
Or we can delete column like this
for x in my_list:
    x.pop(3)
print(my_list)
Creating a two dimensional List by using random numbers
from random import randrange
n=5 # dimension of the matrix 
my_list=[] # declare a list 

for i in range(0,n):
    l1=[]  
    for j in range(0,n):
        x=randrange(10)
        l1.append(x) # adding element to the list 
        
    my_list.append(l1)
print(my_list)
Output
[[5, 1, 7, 6, 6], [9, 0, 1, 1, 2], [9, 2, 2, 7, 4], [6, 2, 6, 9, 6], [7, 1, 6, 4, 5]]

Transpose of a matrix

We used zip here
my_list=[[1,2], [3,4], [5,6]]
for row in my_list:
    print(row)
print("Transpose the matrix")    

#list(map(list, zip(*my_list)))
my_list_T=map(list, zip(*my_list))
list(my_list_T)
Output
[1, 2]
[3, 4]
[5, 6]
Transpose the matrix
[[1, 3, 5], [2, 4, 6]]

Sum of diagonal numbers of a square matrix

my_list=[[1, 0, 0, 4, 6], [3, 9, 8, 0, 0], [3, 9, 1, 1, 5], [0, 9, 3, 0, 8], [8, 6, 1, 9, 7]]
for i in my_list:
    print(i)
Output
[1, 0, 0, 4, 6]
[3, 9, 8, 0, 0]
[3, 9, 1, 1, 5]
[0, 9, 3, 0, 8]
[8, 6, 1, 9, 7]


List Matrix Multiplication without using built-in functions

Python



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