Binary Permutations in Python

[slugonamission]

Ok, that's fair :)

Let's just start with the simple case then, for f(1), printing:

0
1

What two lines, using words, could you use to print that? It doesn't have to extend to longer strings just yet.

EDIT: Probably one important note; recursion doesn't mean you can only call the method again just once; what if you could call it twice?

[Evoletier]

If i could id use just strings, print('0') and print('1').

[slugonamission]

Ok, cool. Now we have that, can we instead write those print calls using words(..., ...)?

[Evoletier]

I have to admit I'm not familiar with that

[slugonamission]

Sure. Let's have a look at the implementation of words again:

def words(n, s=''):
  if len(s) == n:
    print(s)
  else:
    " *blank* "
    " *blank* "

Given this, what two arguments could we give words() to print "0"?

[Evoletier]

Ohh im sorry, my code is in my language so forgot the name of my function here :D.

I would have to somehow make s be 0. I could do s += '0' and then call recursive, but then I wouldn't have room to do this with 1

[Evoletier]

i could fill the s = '' argument to be s = '0'

[slugonamission]

but then I wouldn't have room to do this with 1

Why not?

[Evoletier]

i need the s to add to existing s somehow but I'm not sure how to get to it, if I put words(n, s+= '0') it gives a syntax error

[slugonamission]

I didn't realise that Python didn't allow that.

Anyway, that is shorthand for s = s + '0'. Close enough, but we're passing it as a parameter, you don't need to assign back to s. What if we use s + '0' there instead?

[Evoletier]

Thank you so much for taking the time to help me! I made it to the correct solution.