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from .base import BaseItertool
from .iter_dispatch import iter_
class imap(BaseItertool):
"""imap(func, *iterables) --> imap object
Make an iterator that computes the function using arguments from
each of the iterables. Stops when the shortest iterable is exhausted.
"""
def __init__(self, function, *iterables):
self._function = function
self._iterables = tuple(iter_(it) for it in iterables)
def _run(self, args):
return self._function(*args)
def __next__(self):
args = tuple([next(it) for it in self._iterables])
if self._function is None:
return args
else:
return self._run(args)
class starmap(imap):
"""starmap(function, sequence) --> starmap object
Return an iterator whose values are returned from the function evaluated
with a argument tuple taken from the given sequence.
"""
def __init__(self, function, iterable):
self._iterables = (iter_(iterable),)
self._function = function
def _run(self, args):
return self._function(*args[0])
def izip(*iterables):
"""zip(iter1 [,iter2 [...]]) --> zip object
Return a zip object whose .__next__() method returns a tuple where
the i-th element comes from the i-th iterable argument. The .__next__()
method continues until the shortest iterable in the argument sequence
is exhausted and then it raises StopIteration.
"""
return imap(None, *iterables)
class izip_longest(BaseItertool):
"""zip_longest(iter1 [,iter2 [...]], [fillvalue=None]) --> zip_longest
object
Return an zip_longest object whose .__next__() method returns a tuple where
the i-th element comes from the i-th iterable argument. The .__next__()
method continues until the longest iterable in the argument sequence
is exhausted and then it raises StopIteration. When the shorter iterables
are exhausted, the fillvalue is substituted in their place. The fillvalue
defaults to None or can be specified by a keyword argument.
"""
def __init__(self, *iterables, **kwargs):
if 'fillvalue' in kwargs:
self._fillvalue = kwargs['fillvalue']
del kwargs['fillvalue']
else:
self._fillvalue = None
if len(kwargs) > 0:
raise ValueError("Unrecognized keyword arguments: {}".format(
", ".join(kwargs)))
self._iterables = tuple(iter_(it) for it in iterables)
def __next__(self):
found_any = False
result = []
for it in self._iterables:
try:
result.append(next(it))
found_any = True
except StopIteration:
result.append(self._fillvalue)
if found_any:
return tuple(result)
else:
raise StopIteration
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