def combinations_with_replacement(self, r: int):
"""See itertools.combinations_with_replacement_
.. _itertools.combinations_with_replacement: https://docs.python.org/3/library/itertools.html#itertools.combinations_with_replacement
""" # noqa
this_len = len_or_none(self)
if this_len is None:
length = None
else:
length = nCr(this_len, r, True)
return FIt(combinations_with_replacement(self, r), length)
def test_nCr_edges():
with pytest.raises(ValueError):
nCr(-1, 1)
with pytest.raises(ValueError):
nCr(1, -1)
assert nCr(0, 0) == 0
assert nCr(2, 3) == 0
def combinations(self, r: int, replace=False):
"""See itertools.combinations_
Difference from stdlib: ``replace`` argument to use
itertools.combinations_with_replacement_
.. _itertools.combinations: https://docs.python.org/3/library/itertools.html#itertools.combinations
.. _itertools.combinations_with_replacement: https://docs.python.org/3/library/itertools.html#itertools.combinations_with_replacement
""" # noqa
if replace:
return FIt.combinations_with_replacement(self, r)
this_len = len_or_none(self)
if this_len is None:
length = None
else:
length = nCr(this_len, r)
return FIt(combinations(self, r), length)
def test_nCr_replace():
assert nCr(3, 2, True) == 6
def test_nCr():
assert nCr(3, 2) == 3