Multiple nested loop replacement equivalent in python

Asked Nov 23 '18 at 13:51

Active Nov 23 '18 at 14:05

Viewed 65 times

For any given n , I need the following to happen.

def count(n):
  for i in range(0,5):
    for j in range(0,i+1):
      for k in range(0,j+1):
        .......
          n nested loops 
             count=count+1 
   return count

I would like to know if there is a more concise way of achieving this above code segment.

the code has to return 5,15,35,70 on input of 1,2,3,4 .

edited Nov 23 '18 at 14:05

asked Nov 23 '18 at 13:51

Akash janardhan S

You wrote that there are `n` nested loops. This is not the same `n` as the argument of the function, is it? – syntonym Nov 23 '18 at 13:53
1

Take a look at [this](https://stackoverflow.com/questions/7186518/function-with-varying-number-of-for-loops-python) – jar Nov 23 '18 at 13:56
syntonym , yes , it the same n passed in the argument – Akash janardhan S Nov 23 '18 at 13:58
raj, I had a look at that. That would return 5,25,125 on input of 1,2,3. What I would like is for it to return 5,15,35 for n=1,2,3 . Thanks. – Akash janardhan S Nov 23 '18 at 14:01
There should be a closed-form solution that doesn't involve any loops at all. – mkrieger1 Nov 23 '18 at 14:10
Should count in the last line have an argument? – cardamom Nov 23 '18 at 14:12
yes, some sort of a single line statement involving itertools. – Akash janardhan S Nov 23 '18 at 14:13
cardamon, no it's not recursive, count that needs to be returned is the count that was incremented after that n th nested loop – Akash janardhan S Nov 23 '18 at 14:15
What you want to compute is the binomial coefficient `binomial(n, 4)` (4 being 5–1, from `range(0, 5)`). See https://oeis.org/A000332 – mkrieger1 Nov 23 '18 at 14:19
1

Please don't reuse the name of your function for a local variable in the function, it makes the code harder to read. Do you *have* to do this with nested loops? – PM 2Ring Nov 23 '18 at 14:20
You can use SciPy: https://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.special.binom.html – mkrieger1 Nov 23 '18 at 14:21
[Here](https://stackoverflow.com/a/26561091/4014959) is a simple binomial function that doesn't use any imports. – PM 2Ring Nov 23 '18 at 14:25
Thanks, the binomial function works perfectly for solution i needed. – Akash janardhan S Nov 23 '18 at 14:27

Multiple nested loop replacement equivalent in python

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