number generator

Raymond Hettinger python at rcn.com
Wed Mar 14 10:39:22 CET 2007


[Alex Martelli]
>   map([random.randrange(5) for i in xrange(45)].count, xrange(5))
>
> i.e., this gives 5 integers (each between 0 and 45 included) summing to
> 45 -- add 1 to each of them to get the desired result.

This is a really nice approach.  Besides being fast, it is not too
hard to see that it is correct.

FWIW, here's a variant with a count using the new defaultdict:

n, m = 5, 45
bag = collections.defaultdict(int)
for i in xrange(m):
    bag[random.randrange(n)] += 1
ans = [bag[k] for k in range(n)]




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