CODEWITHSUNDEEP
python
Henrique Lima
Henrique Lima

Reputation: 87

a variable sequence of for in python

I'm starting to program in python and I came across a problem that I don't know how to solve.

I have a nested fors function, where the number of nested fors depends on an input parameter, for example, if I have the input parameter set to 2, I have to have:

for loop1 in range (0, limit):
   for loop2 in range (0, limit):
      print ('loop1: {} loop2: {}'.format(loop1,loop2))

If it is set equal to 3, I must have:

for loop1 in range (0, limit):
   for loop2 in range (0, limit):
      for loop3 in range (0, limit):
         print ('loop1: {} loop2: {} loop3 {}'.format(loop1,loop2, loop3))

The results will be:

for 2:

0,0
0,1
1,0
1,1

for 3:

0,0,0
0,0,1
0,1,0
1,0,0
...
2,2,2

And so on.

Does anyone out there have any idea how to do this?

Upvotes: 0

Views: 256

Answers (4)

Peter M.
Peter M.

Reputation: 124

Seems like something that has to be solved with a recursive function. something like:

def loops(n,limit):
    for loop in range (0, limit):
        n-=1
        row = [loop]
        if n == 1:
            ...
        else:    
            row = row + loops(n,limit)

I didn't have time to finetune, but you get the idea. If not, do some research on recursive functions.

Upvotes: 0

Peilonrayz
Peilonrayz

Reputation: 3914

This is known as a cartesian product and is available in Python via itertools.product

import itertools

for i in itertools.product(range(3), repeat=3):
    print(i)

To specify many you can just enter multiple iterators.

for i in itertools.product(range(1), range(2), range(3)):
    print(i)

Upvotes: 2

Denis Tereshchenko
Denis Tereshchenko

Reputation: 131

You can do:

import itertools

for i in itertools.product(list(range(x)), repeat=x):
    print(','.join(i), end=' ')

itertools.product returns all products of range from 0 to x - 1, then you join and print them.

Upvotes: 1

Cory Kramer
Cory Kramer

Reputation: 117856

You can use itertools.product with the repeat argument to generate these sequences.

from itertools import product

def gen_sequence(limit):
    for vals in product(range(limit), repeat=limit):
        print(','.join(str(i) for i in vals))

Example

>>> gen_sequence(2)
0,0
0,1
1,0
1,1

>>> gen_sequence(3)
0,0,0
0,0,1
0,0,2
...
2,2,0
2,2,1
2,2,2

Upvotes: 3

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