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import numpy as np
import pytest
from pandas._libs.tslibs import IncompatibleFrequency
from pandas import (
DataFrame,
Period,
Series,
Timestamp,
date_range,
period_range,
to_datetime,
)
import pandas._testing as tm
@pytest.fixture
def date_range_frame():
"""
Fixture for DataFrame of ints with date_range index
Columns are ['A', 'B'].
"""
N = 50
rng = date_range("1/1/1990", periods=N, freq="53s")
return DataFrame({"A": np.arange(N), "B": np.arange(N)}, index=rng)
class TestFrameAsof:
def test_basic(self, date_range_frame):
# Explicitly cast to float to avoid implicit cast when setting np.nan
df = date_range_frame.astype({"A": "float"})
N = 50
df.loc[df.index[15:30], "A"] = np.nan
dates = date_range("1/1/1990", periods=N * 3, freq="25s")
result = df.asof(dates)
assert result.notna().all(1).all()
lb = df.index[14]
ub = df.index[30]
dates = list(dates)
result = df.asof(dates)
assert result.notna().all(1).all()
mask = (result.index >= lb) & (result.index < ub)
rs = result[mask]
assert (rs == 14).all(1).all()
def test_subset(self, date_range_frame):
N = 10
# explicitly cast to float to avoid implicit upcast when setting to np.nan
df = date_range_frame.iloc[:N].copy().astype({"A": "float"})
df.loc[df.index[4:8], "A"] = np.nan
dates = date_range("1/1/1990", periods=N * 3, freq="25s")
# with a subset of A should be the same
result = df.asof(dates, subset="A")
expected = df.asof(dates)
tm.assert_frame_equal(result, expected)
# same with A/B
result = df.asof(dates, subset=["A", "B"])
expected = df.asof(dates)
tm.assert_frame_equal(result, expected)
# B gives df.asof
result = df.asof(dates, subset="B")
expected = df.resample("25s", closed="right").ffill().reindex(dates)
expected.iloc[20:] = 9
# no "missing", so "B" can retain int dtype (df["A"].dtype platform-dependent)
expected["B"] = expected["B"].astype(df["B"].dtype)
tm.assert_frame_equal(result, expected)
def test_missing(self, date_range_frame):
# GH 15118
# no match found - `where` value before earliest date in index
N = 10
# Cast to 'float64' to avoid upcast when introducing nan in df.asof
df = date_range_frame.iloc[:N].copy().astype("float64")
result = df.asof("1989-12-31")
expected = Series(
index=["A", "B"], name=Timestamp("1989-12-31"), dtype=np.float64
)
tm.assert_series_equal(result, expected)
result = df.asof(to_datetime(["1989-12-31"]))
expected = DataFrame(
index=to_datetime(["1989-12-31"]), columns=["A", "B"], dtype="float64"
)
tm.assert_frame_equal(result, expected)
# Check that we handle PeriodIndex correctly, dont end up with
# period.ordinal for series name
df = df.to_period("D")
result = df.asof("1989-12-31")
assert isinstance(result.name, Period)
def test_asof_all_nans(self, frame_or_series):
# GH 15713
# DataFrame/Series is all nans
result = frame_or_series([np.nan]).asof([0])
expected = frame_or_series([np.nan])
tm.assert_equal(result, expected)
def test_all_nans(self, date_range_frame):
# GH 15713
# DataFrame is all nans
# testing non-default indexes, multiple inputs
N = 150
rng = date_range_frame.index
dates = date_range("1/1/1990", periods=N, freq="25s")
result = DataFrame(np.nan, index=rng, columns=["A"]).asof(dates)
expected = DataFrame(np.nan, index=dates, columns=["A"])
tm.assert_frame_equal(result, expected)
# testing multiple columns
dates = date_range("1/1/1990", periods=N, freq="25s")
result = DataFrame(np.nan, index=rng, columns=["A", "B", "C"]).asof(dates)
expected = DataFrame(np.nan, index=dates, columns=["A", "B", "C"])
tm.assert_frame_equal(result, expected)
# testing scalar input
result = DataFrame(np.nan, index=[1, 2], columns=["A", "B"]).asof([3])
expected = DataFrame(np.nan, index=[3], columns=["A", "B"])
tm.assert_frame_equal(result, expected)
result = DataFrame(np.nan, index=[1, 2], columns=["A", "B"]).asof(3)
expected = Series(np.nan, index=["A", "B"], name=3)
tm.assert_series_equal(result, expected)
@pytest.mark.parametrize(
"stamp,expected",
[
(
Timestamp("2018-01-01 23:22:43.325+00:00"),
Series(2, name=Timestamp("2018-01-01 23:22:43.325+00:00")),
),
(
Timestamp("2018-01-01 22:33:20.682+01:00"),
Series(1, name=Timestamp("2018-01-01 22:33:20.682+01:00")),
),
],
)
def test_time_zone_aware_index(self, stamp, expected):
# GH21194
# Testing awareness of DataFrame index considering different
# UTC and timezone
df = DataFrame(
data=[1, 2],
index=[
Timestamp("2018-01-01 21:00:05.001+00:00"),
Timestamp("2018-01-01 22:35:10.550+00:00"),
],
)
result = df.asof(stamp)
tm.assert_series_equal(result, expected)
def test_is_copy(self, date_range_frame):
# GH-27357, GH-30784: ensure the result of asof is an actual copy and
# doesn't track the parent dataframe / doesn't give SettingWithCopy warnings
df = date_range_frame.astype({"A": "float"})
N = 50
df.loc[df.index[15:30], "A"] = np.nan
dates = date_range("1/1/1990", periods=N * 3, freq="25s")
result = df.asof(dates)
with tm.assert_produces_warning(None):
result["C"] = 1
def test_asof_periodindex_mismatched_freq(self):
N = 50
rng = period_range("1/1/1990", periods=N, freq="h")
df = DataFrame(np.random.default_rng(2).standard_normal(N), index=rng)
# Mismatched freq
msg = "Input has different freq"
with pytest.raises(IncompatibleFrequency, match=msg):
df.asof(rng.asfreq("D"))
def test_asof_preserves_bool_dtype(self):
# GH#16063 was casting bools to floats
dti = date_range("2017-01-01", freq="MS", periods=4)
ser = Series([True, False, True], index=dti[:-1])
ts = dti[-1]
res = ser.asof([ts])
expected = Series([True], index=[ts])
tm.assert_series_equal(res, expected)