Matteo wrote: > Hi all, > let's see if there is a more "pythonic" way of doing what I'm trying > to do. > I have a lot of strings with numbers like this one: > > string = "-1 1.3 100.136 1 2.6 100.726 1 3.9 101.464 -1 5.2 102.105" > > I need to pass the numbers to a function, but three at a time, until > the string ends. The strings are of variable length, but always a > multiple of three. > > That's what I did: > num = string.split() > for triple in zip(num[::3], num[1::3], num[2::3]): > func(*triple) > > it works and I like slices, but I was wondering if there was another > way of doing the same thing, maybe reading the numbers in groups of > arbitrary length n... > > any ideas?
Ideas? Many. But do they make sense? >>> from itertools import * >>> items = range(10) >>> for chunk in iter((tuple(islice(items, 3)) for items in >>> repeat(iter(items))).next, ()): ... print chunk ... (0, 1, 2) (3, 4, 5) (6, 7, 8) (9,) >>> for chunk in takewhile(bool, (tuple(islice(items, 3)) for items in >>> repeat(iter(items)))): ... print chunk ... (0, 1, 2) (3, 4, 5) (6, 7, 8) (9,) >>> def make_read(items): ... items = iter(items) ... def read(n): ... return tuple(islice(items, n)) ... return read ... >>> from functools import partial >>> for chunk in iter(partial(make_read(items), 3), ()): ... print chunk ... (0, 1, 2) (3, 4, 5) (6, 7, 8) (9,) >>> read = make_read(items) >>> for n in [3,4,2,1]: ... print read(n) ... (0, 1, 2) (3, 4, 5, 6) (7, 8) (9,) >>> items = iter([3, "a", "b", "c", 2, "p", "q", 4, "x", "y", "z", "t"]) >>> read = make_read(items) >>> for n in items: ... print "".join(read(n)) ... abc pq xyzt -- http://mail.python.org/mailman/listinfo/python-list
