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import itertools
from collections import deque
from itertools import islice
# from jaraco.itertools 6.3.0
class Counter:
"""
Wrap an iterable in an object that stores the count of items
that pass through it.
>>> items = Counter(range(20))
>>> items.count
0
>>> values = list(items)
>>> items.count
20
"""
def __init__(self, i):
self.count = 0
self.iter = zip(itertools.count(1), i)
def __iter__(self):
return self
def __next__(self):
self.count, result = next(self.iter)
return result
# from more_itertools v8.13.0
def always_iterable(obj, base_type=(str, bytes)):
if obj is None:
return iter(())
if (base_type is not None) and isinstance(obj, base_type):
return iter((obj,))
try:
return iter(obj)
except TypeError:
return iter((obj,))
# from more_itertools v9.0.0
def consume(iterator, n=None):
"""Advance *iterable* by *n* steps. If *n* is ``None``, consume it
entirely.
Efficiently exhausts an iterator without returning values. Defaults to
consuming the whole iterator, but an optional second argument may be
provided to limit consumption.
>>> i = (x for x in range(10))
>>> next(i)
0
>>> consume(i, 3)
>>> next(i)
4
>>> consume(i)
>>> next(i)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
StopIteration
If the iterator has fewer items remaining than the provided limit, the
whole iterator will be consumed.
>>> i = (x for x in range(3))
>>> consume(i, 5)
>>> next(i)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
StopIteration
"""
# Use functions that consume iterators at C speed.
if n is None:
# feed the entire iterator into a zero-length deque
deque(iterator, maxlen=0)
else:
# advance to the empty slice starting at position n
next(islice(iterator, n, n), None)
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