from datetime import datetime
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import pytest
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import pytz
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from pandas.errors import NullFrequencyError
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import pandas as pd
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from pandas import (
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DatetimeIndex,
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Series,
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date_range,
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)
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import pandas._testing as tm
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START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
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class TestDatetimeIndexShift:
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# -------------------------------------------------------------
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# DatetimeIndex.shift is used in integer addition
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def test_dti_shift_tzaware(self, tz_naive_fixture):
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# GH#9903
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tz = tz_naive_fixture
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idx = DatetimeIndex([], name="xxx", tz=tz)
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tm.assert_index_equal(idx.shift(0, freq="H"), idx)
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tm.assert_index_equal(idx.shift(3, freq="H"), idx)
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idx = DatetimeIndex(
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["2011-01-01 10:00", "2011-01-01 11:00", "2011-01-01 12:00"],
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name="xxx",
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tz=tz,
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freq="H",
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)
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tm.assert_index_equal(idx.shift(0, freq="H"), idx)
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exp = DatetimeIndex(
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["2011-01-01 13:00", "2011-01-01 14:00", "2011-01-01 15:00"],
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name="xxx",
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tz=tz,
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freq="H",
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)
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tm.assert_index_equal(idx.shift(3, freq="H"), exp)
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exp = DatetimeIndex(
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["2011-01-01 07:00", "2011-01-01 08:00", "2011-01-01 09:00"],
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name="xxx",
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tz=tz,
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freq="H",
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)
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tm.assert_index_equal(idx.shift(-3, freq="H"), exp)
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def test_dti_shift_freqs(self):
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# test shift for DatetimeIndex and non DatetimeIndex
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# GH#8083
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drange = date_range("20130101", periods=5)
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result = drange.shift(1)
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expected = DatetimeIndex(
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["2013-01-02", "2013-01-03", "2013-01-04", "2013-01-05", "2013-01-06"],
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freq="D",
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)
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tm.assert_index_equal(result, expected)
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result = drange.shift(-1)
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expected = DatetimeIndex(
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["2012-12-31", "2013-01-01", "2013-01-02", "2013-01-03", "2013-01-04"],
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freq="D",
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)
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tm.assert_index_equal(result, expected)
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result = drange.shift(3, freq="2D")
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expected = DatetimeIndex(
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["2013-01-07", "2013-01-08", "2013-01-09", "2013-01-10", "2013-01-11"],
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freq="D",
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)
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tm.assert_index_equal(result, expected)
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def test_dti_shift_int(self):
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rng = date_range("1/1/2000", periods=20)
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result = rng + 5 * rng.freq
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expected = rng.shift(5)
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tm.assert_index_equal(result, expected)
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result = rng - 5 * rng.freq
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expected = rng.shift(-5)
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tm.assert_index_equal(result, expected)
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def test_dti_shift_no_freq(self):
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# GH#19147
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dti = DatetimeIndex(["2011-01-01 10:00", "2011-01-01"], freq=None)
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with pytest.raises(NullFrequencyError, match="Cannot shift with no freq"):
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dti.shift(2)
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@pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
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def test_dti_shift_localized(self, tzstr):
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dr = date_range("2011/1/1", "2012/1/1", freq="W-FRI")
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dr_tz = dr.tz_localize(tzstr)
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result = dr_tz.shift(1, "10T")
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assert result.tz == dr_tz.tz
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def test_dti_shift_across_dst(self):
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# GH 8616
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idx = date_range("2013-11-03", tz="America/Chicago", periods=7, freq="H")
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s = Series(index=idx[:-1], dtype=object)
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result = s.shift(freq="H")
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expected = Series(index=idx[1:], dtype=object)
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tm.assert_series_equal(result, expected)
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@pytest.mark.parametrize(
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"shift, result_time",
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[
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[0, "2014-11-14 00:00:00"],
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[-1, "2014-11-13 23:00:00"],
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[1, "2014-11-14 01:00:00"],
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],
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)
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def test_dti_shift_near_midnight(self, shift, result_time):
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# GH 8616
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dt = datetime(2014, 11, 14, 0)
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dt_est = pytz.timezone("EST").localize(dt)
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s = Series(data=[1], index=[dt_est])
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result = s.shift(shift, freq="H")
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expected = Series(1, index=DatetimeIndex([result_time], tz="EST"))
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tm.assert_series_equal(result, expected)
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def test_shift_periods(self):
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# GH#22458 : argument 'n' was deprecated in favor of 'periods'
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idx = date_range(start=START, end=END, periods=3)
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tm.assert_index_equal(idx.shift(periods=0), idx)
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tm.assert_index_equal(idx.shift(0), idx)
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@pytest.mark.parametrize("freq", ["B", "C"])
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def test_shift_bday(self, freq):
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rng = date_range(START, END, freq=freq)
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shifted = rng.shift(5)
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assert shifted[0] == rng[5]
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assert shifted.freq == rng.freq
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shifted = rng.shift(-5)
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assert shifted[5] == rng[0]
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assert shifted.freq == rng.freq
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shifted = rng.shift(0)
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assert shifted[0] == rng[0]
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assert shifted.freq == rng.freq
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def test_shift_bmonth(self):
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rng = date_range(START, END, freq=pd.offsets.BMonthEnd())
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shifted = rng.shift(1, freq=pd.offsets.BDay())
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assert shifted[0] == rng[0] + pd.offsets.BDay()
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rng = date_range(START, END, freq=pd.offsets.BMonthEnd())
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with tm.assert_produces_warning(pd.errors.PerformanceWarning):
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shifted = rng.shift(1, freq=pd.offsets.CDay())
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assert shifted[0] == rng[0] + pd.offsets.CDay()
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def test_shift_empty(self):
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# GH#14811
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dti = date_range(start="2016-10-21", end="2016-10-21", freq="BM")
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result = dti.shift(1)
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tm.assert_index_equal(result, dti)
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