bpo-42450: Minor updates to the itertools recipes (GH-23555)

This commit is contained in:
Raymond Hettinger 2020-11-29 10:47:22 -08:00 committed by GitHub
parent 86684319d3
commit fc40b3020c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 7 additions and 7 deletions

View File

@ -755,7 +755,7 @@ which incur interpreter overhead.
"Count how many times the predicate is true"
return sum(map(pred, iterable))
def padnone(iterable):
def pad_none(iterable):
"""Returns the sequence elements and then returns None indefinitely.
Useful for emulating the behavior of the built-in map() function.
@ -809,7 +809,7 @@ which incur interpreter overhead.
nexts = cycle(islice(nexts, num_active))
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"
# partition(is_odd, range(10)) --> 0 2 4 6 8 and 1 3 5 7 9
t1, t2 = tee(iterable)
return filterfalse(pred, t1), filter(pred, t2)
@ -881,7 +881,7 @@ which incur interpreter overhead.
def random_product(*args, repeat=1):
"Random selection from itertools.product(*args, **kwds)"
pools = [tuple(pool) for pool in args] * repeat
return tuple(random.choice(pool) for pool in pools)
return tuple(map(random.choice, pools))
def random_permutation(iterable, r=None):
"Random selection from itertools.permutations(iterable, r)"
@ -900,11 +900,11 @@ which incur interpreter overhead.
"Random selection from itertools.combinations_with_replacement(iterable, r)"
pool = tuple(iterable)
n = len(pool)
indices = sorted(random.randrange(n) for i in range(r))
indices = sorted(random.choices(range(n), k=r))
return tuple(pool[i] for i in indices)
def nth_combination(iterable, r, index):
'Equivalent to list(combinations(iterable, r))[index]'
"Equivalent to list(combinations(iterable, r))[index]"
pool = tuple(iterable)
n = len(pool)
if r < 0 or r > n:

View File

@ -2290,7 +2290,7 @@ Samuele
... "Count how many times the predicate is true"
... return sum(map(pred, iterable))
>>> def padnone(iterable):
>>> def pad_none(iterable):
... "Returns the sequence elements and then returns None indefinitely"
... return chain(iterable, repeat(None))
@ -2460,7 +2460,7 @@ True
>>> list(pairwise('a'))
[]
>>> list(islice(padnone('abc'), 0, 6))
>>> list(islice(pad_none('abc'), 0, 6))
['a', 'b', 'c', None, None, None]
>>> list(ncycles('abc', 3))