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from .base import BaseItertool
from .iter_dispatch import iter_
class _grouper(BaseItertool):
def __init__(self, value, iterator, groupby_obj):
self._value = value
self._groupby = groupby_obj
self._key = self._groupby.key(self._value)
self._initialized = False
self._iterator = iterator
self.stream_ended = False
self._done = False
def __next__(self):
if not self._initialized:
self._initialized = True
return self._value
else:
if self._done:
raise StopIteration
try:
value = next(self._iterator)
except StopIteration:
self.stream_ended = True
self._done = True
raise
if self._groupby.key(value) != self._key:
self.terminal_value = value
self._done = True
raise StopIteration
return value
class groupby(BaseItertool):
"""groupby(iterable[, keyfunc]) -> create an iterator which returns
(key, sub-iterator) grouped by each value of key(value).
"""
def __init__(self, iterable, key=None):
self._keyfunc = key
self._iterator = iter_(iterable)
self._current_key = self._initial_key = object()
def key(self, value):
if self._keyfunc is None:
return value
else:
return self._keyfunc(value)
def __next__(self):
if not hasattr(self, '_current_grouper'):
value = next(self._iterator)
self._current_grouper = _grouper(value, self._iterator, self)
return self.key(value), self._current_grouper
else:
while True:
try:
next(self._current_grouper)
except StopIteration:
break
if self._current_grouper.stream_ended:
raise StopIteration
value = self._current_grouper.terminal_value
self._current_grouper = _grouper(value, self._iterator, self)
return self.key(value), self._current_grouper
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