def cftime_start_time(date, freq):
"""Get the cftime.datetime for the start of a period.
As we are not supplying actual period objects, assumptions regarding the period are made based on
the given freq. IMPORTANT NOTE: this function cannot be used on greater-than-day freq that start at the
beginning of a month, e.g. 'MS', 'QS', 'AS' -- this mirrors pandas behavior.
Parameters
----------
date : cftime.datetime
The original datetime object as a proxy representation for period.
freq : str
String specifying the frequency/offset such as 'MS', '2D', 'H', or '3T'
Returns
-------
cftime.datetime
The starting datetime of the period inferred from date and freq.
"""
freq = to_offset(freq)
if isinstance(freq, (YearBegin, QuarterBegin, MonthBegin)):
raise ValueError("Invalid frequency: " + freq.rule_code())
if isinstance(freq, YearEnd):
month = freq.month
return date - YearEnd(n=1, month=month) + pydt.timedelta(days=1)
if isinstance(freq, QuarterEnd):
month = freq.month
return date - QuarterEnd(n=1, month=month) + pydt.timedelta(days=1)
if isinstance(freq, MonthEnd):
return date - MonthEnd(n=1) + pydt.timedelta(days=1)
return date
[(BaseCFTimeOffset(), '<BaseCFTimeOffset: n=1>'),
(YearBegin(), '<YearBegin: n=1, month=1>')],
ids=_id_func)
def test_str_and_repr(offset, expected):
assert str(offset) == expected
assert repr(offset) == expected
@pytest.mark.parametrize(
'offset', [BaseCFTimeOffset(),
MonthBegin(), YearBegin()], ids=_id_func)
def test_to_offset_offset_input(offset):
assert to_offset(offset) == offset
@pytest.mark.parametrize(('freq', 'expected'), [('M', MonthEnd()),
('2M', MonthEnd(n=2)),
('MS', MonthBegin()),
('2MS', MonthBegin(n=2)),
('D', Day()), ('2D', Day(n=2)),
('H', Hour()),
('2H', Hour(n=2)),
('T', Minute()),
('2T', Minute(n=2)),
('min', Minute()),
('2min', Minute(n=2)),
('S', Second()),
('2S', Second(n=2))],
ids=_id_func)
def test_to_offset_sub_annual(freq, expected):
assert to_offset(freq) == expected
assert str(offset) == expected
assert repr(offset) == expected
@pytest.mark.parametrize(
'offset',
[BaseCFTimeOffset(), MonthBegin(), QuarterBegin(), YearBegin()],
ids=_id_func
)
def test_to_offset_offset_input(offset):
assert to_offset(offset) == offset
@pytest.mark.parametrize(
('freq', 'expected'),
[('M', MonthEnd()),
('2M', MonthEnd(n=2)),
('MS', MonthBegin()),
('2MS', MonthBegin(n=2)),
('D', Day()),
('2D', Day(n=2)),
('H', Hour()),
('2H', Hour(n=2)),
('T', Minute()),
('2T', Minute(n=2)),
('min', Minute()),
('2min', Minute(n=2)),
('S', Second()),
('2S', Second(n=2))],
ids=_id_func
)
@pytest.mark.parametrize(
"offset",
[BaseCFTimeOffset(),
MonthBegin(),
QuarterBegin(),
YearBegin()],
ids=_id_func,
)
def test_to_offset_offset_input(offset):
assert to_offset(offset) == offset
@pytest.mark.parametrize(
("freq", "expected"),
[
("M", MonthEnd()),
("2M", MonthEnd(n=2)),
("MS", MonthBegin()),
("2MS", MonthBegin(n=2)),
("D", Day()),
("2D", Day(n=2)),
("H", Hour()),
("2H", Hour(n=2)),
("T", Minute()),
("2T", Minute(n=2)),
("min", Minute()),
("2min", Minute(n=2)),
("S", Second()),
("2S", Second(n=2)),
],
ids=_id_func,
assert repr(offset) == expected
@pytest.mark.parametrize(
"offset",
[BaseCFTimeOffset(), MonthBegin(), QuarterBegin(), YearBegin()],
ids=_id_func,
)
def test_to_offset_offset_input(offset):
assert to_offset(offset) == offset
@pytest.mark.parametrize(
("freq", "expected"),
[
("M", MonthEnd()),
("2M", MonthEnd(n=2)),
("MS", MonthBegin()),
("2MS", MonthBegin(n=2)),
("D", Day()),
("2D", Day(n=2)),
("H", Hour()),
("2H", Hour(n=2)),
("T", Minute()),
("2T", Minute(n=2)),
("min", Minute()),
("2min", Minute(n=2)),
("S", Second()),
("2S", Second(n=2)),
("L", Millisecond(n=1)),
("2L", Millisecond(n=2)),