How to input element in 2d array

Question

Like below C++ Code, how could I use Python to input elements in 2d array? Please, help in writing the same program in Python3.

int main()
{
 int s = 3;
 int a[s][s];
 cout<<"Enter 9 Element in Square Matrix";
 for(int i =0;i<s;i++)
 {
  for(int j =0; j<s;j++)
  {
   cin>>a[i][j];
  }
 }
 cout<<"You Entered";
 for(int i =0;i<s;i++)
 {
  for(int j =0; j<s;j++)
  {
   cout<<a[i][j]<<"\t";
  }
 cout<<endl;
 }
return 0;
}
Output:
Enter 9 Elements in Square Matrix
1
2
3
4
5
6
7
8
9
You Entered: 
1 2 3
4 5 6
7 8 9

If there is a mistake in the program, please don't try to correct it. Thank you.

Can you post what you have tried so far in Python and where in the Python code you are having trouble please — johnashu, Sep 21 '17 at 15:07
Welcome to SO! Please take the [tour] and read [MCVE]. Please note that SO is not a code writing service. — Shawn Mehan, Sep 21 '17 at 15:12
Possible duplicate of [How to input matrix (2D list) in Python?](https://stackoverflow.com/questions/22741030/how-to-input-matrix-2d-list-in-python) — Georgy, Jul 12 '19 at 09:33

Kaushik NP · Accepted Answer · 2017-09-21T15:26:20.600

Am gonna use list to store the 2D array here. There are many other structures you can use for storing a 2D array, but for basic needs, this will suffice.

n=int(input("Enter N for N x N matrix : "))         #3 here
l=[]                                                #use list for storing 2D array

#get the user input and store it in list (here IN : 1 to 9)
for i in range(n): 
  row_list=[]                                      #temporary list to store the row
  for j in range(n): 
     row_list.append(int(input()))                 #add the input to row list
  l.append(row_list)                               #add the row to the list

print(l)
# [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

#Display the 2D array
for i in range(n):
  for j in range(n):
    print(l[i][j], end=" ")
  print()                                           #new line

'''
1 2 3 
4 5 6 
7 8 9 
'''

Sorry, didn't get you. You asking how to access data in the 2D list? If so, it is as you would do in C. Like here `print(l[0][0])` will give `1` — Kaushik NP, Sep 21 '17 at 16:40

score 1 · Answer 2 · answered Sep 21 '17 at 15:32

1

s = 3
a = [x[:] for x in [[0] * s] * s]

print("Enter 9 Element in Square Matrix")

for i in range(0, s):
    for j in range(0, s):
        a[i][j] = input()

print("You Entered")

for i in range(0, s):
    line = ''
    for j in range(0, s):
        line += a[i][j] + ' '
    print(line)

answered Sep 21 '17 at 15:32

Snochacz

685
1
8
23

why you use 2 line? – Himanshu Rastogi Sep 21 '17 at 16:38
Because _print_ has built-in newline and I want to print all of them in the same line. Another way around is importing _sys_ and using _sys.stdout.write()_ – Snochacz Sep 21 '17 at 19:07

score 1 · Answer 3 · answered Sep 21 '17 at 15:35

1

If you are not familiar with python, you should create a file called, for example, matrix.py and then add the following content:

matrix_size = 3
matrix = []

print("Enter {} Elements in Square Matrix:".format(matrix_size))
for i in range(0, matrix_size):
    row = []
    for j in range(0, matrix_size):
        row.append(input())
    matrix.append(row)

print("You entered:")
for i in range(0, matrix_size):
    print(" ".join(matrix[i]))

After saving the file, you can execute this file this way:

python3 matrix.py

Here is a sample output:

[martin@M7 tmp]$ python3 matrix.py
Enter 3 Elements in Square Matrix:
1
2
3
1
2
3
7
5
4
You entered:
1 2 3
1 2 3
7 5 4

answered Sep 21 '17 at 15:35

Martin Castro Alvarez

463
3
11

Thanks, but why you put 0 in Range? – Himanshu Rastogi Sep 21 '17 at 16:28
range(0, n) returns all the values in the following set: {0, 1, 2, ... n-1}. Arrays (and matrices) start at position 0. As a consequence, iterating in range(0, 9) will give you the values in {0, 1, 2, 3, 4, 5, 6, 7, 8} which account for the 9 position that you want to use in your example. – Martin Castro Alvarez Sep 21 '17 at 17:00

score 0 · Answer 4 · answered Nov 05 '18 at 16:41

Say you want to create a 3*3 matrix:

Initialize the matrix as follows:

matrix = [x[:] for x in [[0] * 0] * 0]

Then take the matrix elements as input from the user:

    for i in range(0,3):
        row_list = []
        for j in range(0,3):
            row_list.append(int(input()))
        matrix.append(row_list)

How to input element in 2d array

4 Answers4