Add comment and improve variable name in roundrobin() (GH-4486) (#4487)

(cherry picked from commit 337cbbace0)
This commit is contained in:
Miss Islington (bot) 2017-11-21 00:29:34 -08:00 committed by Raymond Hettinger
parent 60a376cf00
commit 32b003aca3

View file

@ -753,15 +753,16 @@ which incur interpreter overhead.
def roundrobin(*iterables): def roundrobin(*iterables):
"roundrobin('ABC', 'D', 'EF') --> A D E B F C" "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
# Recipe credited to George Sakkis # Recipe credited to George Sakkis
pending = len(iterables) num_active = len(iterables)
nexts = cycle(iter(it).__next__ for it in iterables) nexts = cycle(iter(it).__next__ for it in iterables)
while pending: while num_active:
try: try:
for next in nexts: for next in nexts:
yield next() yield next()
except StopIteration: except StopIteration:
pending -= 1 # Remove the iterator we just exhausted from the cycle.
nexts = cycle(islice(nexts, pending)) num_active -= 1
nexts = cycle(islice(nexts, num_active))
def partition(pred, iterable): def partition(pred, iterable):
'Use a predicate to partition entries into false entries and true entries' 'Use a predicate to partition entries into false entries and true entries'