calculating binomial coefficients using itertools
Ian Kelly
ian.g.kelly at gmail.com
Sat Jul 6 03:11:01 EDT 2013
On Fri, Jul 5, 2013 at 4:58 PM, Robert Hunter <bobjim.hunter at gmail.com> wrote:
> from itertools import count, repeat, izip, starmap
>
> def binomial(n):
> """Calculate list of Nth-order binomial coefficients using itertools."""
>
> l = range(2)
> for _ in xrange(n):
> indices = izip(count(-1), count(1), repeat(1, len(l) + 1))
> slices = starmap(slice, indices)
> l = [sum(l[s]) for s in slices]
> return l[1:]
Nice, I like seeing interesting ways to use slice. This will be more
efficient, though:
def binomial(n):
value = 1
for i in range(n+1):
yield value
value = value * (n-i) // (i+1)
More information about the Python-list
mailing list