Paul Rubin wrote:
> I think the natural approach is to make a generator that yields a
> 5-tuple for each combination, and then have your application iterate
> over that generator. Here's my version:
>
> def comb(x,n):
> """Generate combinations of n items from list x"""
> if n==0:
> yield []
> return
> for i in xrange(len(x)-n+1):
> for r in comb(x[i+1:], n-1):
> yield [x[i]] + r
>
> for c in comb([1,2,3,4,5], 3):
> print c
>
> The output is:
> >>>
> [1, 2, 3]
> [1, 2, 4]
> [1, 2, 5]
> [1, 3, 4]
> [1, 3, 5]
> [1, 4, 5]
> [2, 3, 4]
> [2, 3, 5]
> [2, 4, 5]
> [3, 4, 5]
> >>>
Ah, this definitely seems to work! It's a lot nicer in appearance than
my previous code, that's for sure. It actually runs in approximately
the same amount of time though. So, using your comb method, I have the
following code now:
myCombinations = comb(myList, 5)
for a, b, c, d, e in myCombinations:
# my code
myList is 48 elements in size, so I'm going to get 1712304
combinations. From what I can tell, my speed problems aren't in the
list generation anymore.
Thanks for the assistance, Paul! I appreciate it. :)
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