Answer by doctorzeb8 for How can I partition (split up, divide) a list based...
solutionfrom itertools import teedef unpack_args(fn): return lambda t: fn(*t)def separate(fn, lx): return map( unpack_args( lambda i, ly: filter( lambda el: bool(i) == fn(el), ly)), enumerate(tee(lx,...
View ArticleAnswer by Hanfei Sun for How can I partition (split up, divide) a list based...
def partition(pred, iterable):'Use a predicate to partition entries into false entries and true entries' # partition(is_odd, range(10)) --> 0 2 4 6 8 and 1 3 5 7 9 t1, t2 = tee(iterable) return...
View ArticleAnswer by Jim Witschey for How can I partition (split up, divide) a list...
I'd take a 2-pass approach, separating evaluation of the predicate from filtering the list:def partition(pred, iterable): xs = list(zip(map(pred, iterable), iterable)) return [x[1] for x in xs if...
View ArticleAnswer by Shreyas for How can I partition (split up, divide) a list based on...
Already quite a few solutions here, but yet another way of doing that would be -anims = []images = [f for f in files if (lambda t: True if f[2].lower() in IMAGE_TYPES else anims.append(t) and...
View ArticleAnswer by emvee for How can I partition (split up, divide) a list based on a...
def partition(pred, seq): return reduce( lambda (yes, no), x: (yes+[x], no) if pred(x) else (yes, no+[x]), seq, ([], []) )
View ArticleAnswer by Josh Bode for How can I partition (split up, divide) a list based...
Inspired by @gnibbler's great (but terse!) answer, we can apply that approach to map to multiple partitions:from collections import defaultdictdef splitter(l, mapper):"""Split an iterable into multiple...
View ArticleAnswer by John La Rooy for How can I partition (split up, divide) a list...
Iterate manually, using the condition to select a list to which each element will be appended:good, bad = [], []for x in mylist: (bad, good)[x in goodvals].append(x)
View ArticleAnswer by jcb for How can I partition (split up, divide) a list based on a...
If your concern is not to use two lines of code for an operation whose semantics only need once you just wrap some of the approaches above (even your own) in a single function:def...
View ArticleAnswer by sastanin for How can I partition (split up, divide) a list based on...
My take on it. I propose a lazy, single-pass, partition function,which preserves relative order in the output subsequences.1. RequirementsI assume that the requirements are:maintain elements' relative...
View ArticleAnswer by Shikhar Mall for How can I partition (split up, divide) a list...
Sometimes you won't need that other half of the list.For example:import sysfrom itertools import ifiltertrustedPeople = sys.argv[1].split(',')newName = sys.argv[2]myFriends = ifilter(lambda x:...
View ArticleAnswer by Alan Isaac for How can I partition (split up, divide) a list based...
I basically like Anders' approach as it is very general. Here's a version that puts the categorizer first (to match filter syntax) and uses a defaultdict (assumed imported).def categorize(func,...
View ArticleAnswer by kxmh42 for How can I partition (split up, divide) a list based on a...
If you want to make it in FP style:good, bad = [ sum(x, []) for x in zip(*(([y], []) if y in goodvals else ([], [y]) for y in mylist)) ]Not the most readable solution, but at least iterates through...
View ArticleAnswer by Brian for How can I partition (split up, divide) a list based on a...
itertools.groupby almost does what you want, except it requires the items to be sorted to ensure that you get a single contiguous range, so you need to sort by your key first (otherwise you'll get...
View ArticleAnswer by dbr for How can I partition (split up, divide) a list based on a...
good = [x for x in mylist if x in goodvals]bad = [x for x in mylist if x not in goodvals]is there a more elegant way to do this?That code is perfectly readable, and extremely clear!# files looks like:...
View ArticleAnswer by Anders Eurenius for How can I partition (split up, divide) a list...
If you insist on clever, you could take Winden's solution and just a bit spurious cleverness:def splay(l, f, d=None): d = d or {} for x in l: d.setdefault(f(x), []).append(x) return d
View ArticleAnswer by Ants Aasma for How can I partition (split up, divide) a list based...
Here's the lazy iterator approach:from itertools import teedef split_on_condition(seq, condition): l1, l2 = tee((condition(item), item) for item in seq) return (i for p, i in l1 if p), (i for p, i in...
View ArticleAnswer by winden for How can I partition (split up, divide) a list based on a...
Problem with all proposed solutions is that it will scan and apply the filtering function twice. I'd make a simple small function like this:def split_into_two_lists(lst, f): a = [] b = [] for elem in...
View ArticleAnswer by gimel for How can I partition (split up, divide) a list based on a...
For perfomance, try itertools.The itertools module standardizes a core set of fast, memory efficient tools that are useful by themselves or in combination. Together, they form an “iterator algebra”...
View ArticleAnswer by BJ Homer for How can I partition (split up, divide) a list based on...
Personally, I like the version you cited, assuming you already have a list of goodvals hanging around. If not, something like:good = filter(lambda x: is_good(x), mylist)bad = filter(lambda x: not...
View ArticleAnswer by RichieHindle for How can I partition (split up, divide) a list...
First go (pre-OP-edit): Use sets:mylist = [1,2,3,4,5,6,7]goodvals = [1,3,7,8,9]myset = set(mylist)goodset = set(goodvals)print list(myset.intersection(goodset)) # [1, 3, 7]print...
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