Hi Folks I have this situation
from timeit import Timer reps = 5
t = Timer('itertools.combinations(range(1,10),3)', 'import itertools') print sum(t.repeat(repeat=reps, number=1)) / reps 1.59740447998e-05 t = Timer('itertools.combinations(range(1,100),3)', 'import itertools') print sum(t.repeat(repeat=reps, number=1)) / reps 1.74999237061e-05
t = Timer('list(itertools.combinations(range(1,10),3))', 'import itertools') print sum(t.repeat(repeat=reps, number=1)) / reps 5.31673431396e-05 t = Timer('list(itertools.combinations(range(1,100),3))', 'import itertools') print sum(t.repeat(repeat=reps, number=1)) / reps 0.0556231498718
You can see list(itertools.combinations(range(1,100),3)) is terrible!! If you change to range(1,100000) your computer will lock. So I would like to know a good way to convert <itertools.combinations object> to ndarray? fast! without use list Is it possible?
x = itertools.combinations(range(1,10),3) x <itertools.combinations object at 0x25f1520>
I tried this from http://docs.python.org/library/itertools.html?highlight=itertools#itertools....
numpy.fromiter(itertools.combinations(range(1,10),3), int, count=-1) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: setting an array element with a sequence.
and this from http://docs.python.org/library/itertools.html?highlight=itertools#itertools.... import numpy from itertools import * from numpy import * def combinations(iterable, r): pool = tuple(iterable) n = len(pool) for indices in permutations(range(n), r): if sorted(indices) == list(indices): yield tuple(pool[i] for i in indices) numpy.fromiter(combinations(range(1,10),3), int, count=-1)
numpy.fromiter(combinations(range(1,10),3), int, count=-1) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: setting an array element with a sequence.
I like itertools.combinations performance but I need convert it to numpy. Best Regards mario