How do you use the range function to count from 0 to 8 by increments of 1 for each iteration in a for loop

Question

I have a triple for loop that creates a 1 row and 2 column collection of numbers starting at 0 0 and going up to 2 2. The third for loop counts from 0 to 8. The code looks as follows:

for N in range(0,3):
    for K in range(0,3):
        print(N,K)
        for P in range(0,9):
            print(P)

If you run this code you get the obvious output:

0 0
0
1
2
3
4
5
6
7
8
0 1
0
1
2
3
4
5
6
7
8
0 2
0 
1
2
3
4
5
6
7
8
...

And so on. I want instead of the output of 0 to 8 after the NK printout, instead something that looks like:

0 0 
0
0 1
1
0 2
2
1 0
3
1 1
4
1 2
5
2 0
6
2 1
7
2 2
8

My first guess was an if statement that said:

if P == Q:
   break

where Q was several sets of sums and even the N,K array. However, I couldn't figure out the best way to get my wanted output. I do think an if statement is the best way to achieve my wanted result, but I'm not quite sure of how to approach it. P is necessary for the rest of my code as it will be used in some subplots.

Answer 1

As this is just an increment by one at each print, you can just do compute the index with N * 3 + K

for N in range(0, 3):
    for K in range(0, 3):
        print(N, K)
        print(N * 3 + K)

CODE DEMO

Answer 2

You can use zip to traverse two iterables in parallel. In this case, one of the iterables is the result of a nested list. That can be handled by using itertools.product , as follows:

import itertools

for (N, K), P in zip(itertools.product(range(3), range(3)), range(9)):
    print(N, K)
    print(P)