3RNN/Lib/site-packages/pandas/tests/indexing/test_chaining_and_caching.py
2024-05-26 19:49:15 +02:00

648 lines
23 KiB
Python

from string import ascii_letters
import numpy as np
import pytest
from pandas.errors import (
SettingWithCopyError,
SettingWithCopyWarning,
)
import pandas.util._test_decorators as td
import pandas as pd
from pandas import (
DataFrame,
Index,
Series,
Timestamp,
date_range,
option_context,
)
import pandas._testing as tm
msg = "A value is trying to be set on a copy of a slice from a DataFrame"
def random_text(nobs=100):
# Construct a DataFrame where each row is a random slice from 'letters'
idxs = np.random.default_rng(2).integers(len(ascii_letters), size=(nobs, 2))
idxs.sort(axis=1)
strings = [ascii_letters[x[0] : x[1]] for x in idxs]
return DataFrame(strings, columns=["letters"])
class TestCaching:
def test_slice_consolidate_invalidate_item_cache(self, using_copy_on_write):
# this is chained assignment, but will 'work'
with option_context("chained_assignment", None):
# #3970
df = DataFrame({"aa": np.arange(5), "bb": [2.2] * 5})
# Creates a second float block
df["cc"] = 0.0
# caches a reference to the 'bb' series
df["bb"]
# Assignment to wrong series
with tm.raises_chained_assignment_error():
df["bb"].iloc[0] = 0.17
df._clear_item_cache()
if not using_copy_on_write:
tm.assert_almost_equal(df["bb"][0], 0.17)
else:
# with ArrayManager, parent is not mutated with chained assignment
tm.assert_almost_equal(df["bb"][0], 2.2)
@pytest.mark.parametrize("do_ref", [True, False])
def test_setitem_cache_updating(self, do_ref):
# GH 5424
cont = ["one", "two", "three", "four", "five", "six", "seven"]
df = DataFrame({"a": cont, "b": cont[3:] + cont[:3], "c": np.arange(7)})
# ref the cache
if do_ref:
df.loc[0, "c"]
# set it
df.loc[7, "c"] = 1
assert df.loc[0, "c"] == 0.0
assert df.loc[7, "c"] == 1.0
def test_setitem_cache_updating_slices(
self, using_copy_on_write, warn_copy_on_write
):
# GH 7084
# not updating cache on series setting with slices
expected = DataFrame(
{"A": [600, 600, 600]}, index=date_range("5/7/2014", "5/9/2014")
)
out = DataFrame({"A": [0, 0, 0]}, index=date_range("5/7/2014", "5/9/2014"))
df = DataFrame({"C": ["A", "A", "A"], "D": [100, 200, 300]})
# loop through df to update out
six = Timestamp("5/7/2014")
eix = Timestamp("5/9/2014")
for ix, row in df.iterrows():
out.loc[six:eix, row["C"]] = out.loc[six:eix, row["C"]] + row["D"]
tm.assert_frame_equal(out, expected)
tm.assert_series_equal(out["A"], expected["A"])
# try via a chain indexing
# this actually works
out = DataFrame({"A": [0, 0, 0]}, index=date_range("5/7/2014", "5/9/2014"))
out_original = out.copy()
for ix, row in df.iterrows():
v = out[row["C"]][six:eix] + row["D"]
with tm.raises_chained_assignment_error(
(ix == 0) or warn_copy_on_write or using_copy_on_write
):
out[row["C"]][six:eix] = v
if not using_copy_on_write:
tm.assert_frame_equal(out, expected)
tm.assert_series_equal(out["A"], expected["A"])
else:
tm.assert_frame_equal(out, out_original)
tm.assert_series_equal(out["A"], out_original["A"])
out = DataFrame({"A": [0, 0, 0]}, index=date_range("5/7/2014", "5/9/2014"))
for ix, row in df.iterrows():
out.loc[six:eix, row["C"]] += row["D"]
tm.assert_frame_equal(out, expected)
tm.assert_series_equal(out["A"], expected["A"])
def test_altering_series_clears_parent_cache(
self, using_copy_on_write, warn_copy_on_write
):
# GH #33675
df = DataFrame([[1, 2], [3, 4]], index=["a", "b"], columns=["A", "B"])
ser = df["A"]
if using_copy_on_write or warn_copy_on_write:
assert "A" not in df._item_cache
else:
assert "A" in df._item_cache
# Adding a new entry to ser swaps in a new array, so "A" needs to
# be removed from df._item_cache
ser["c"] = 5
assert len(ser) == 3
assert "A" not in df._item_cache
assert df["A"] is not ser
assert len(df["A"]) == 2
class TestChaining:
def test_setitem_chained_setfault(self, using_copy_on_write):
# GH6026
data = ["right", "left", "left", "left", "right", "left", "timeout"]
mdata = ["right", "left", "left", "left", "right", "left", "none"]
df = DataFrame({"response": np.array(data)})
mask = df.response == "timeout"
with tm.raises_chained_assignment_error():
df.response[mask] = "none"
if using_copy_on_write:
tm.assert_frame_equal(df, DataFrame({"response": data}))
else:
tm.assert_frame_equal(df, DataFrame({"response": mdata}))
recarray = np.rec.fromarrays([data], names=["response"])
df = DataFrame(recarray)
mask = df.response == "timeout"
with tm.raises_chained_assignment_error():
df.response[mask] = "none"
if using_copy_on_write:
tm.assert_frame_equal(df, DataFrame({"response": data}))
else:
tm.assert_frame_equal(df, DataFrame({"response": mdata}))
df = DataFrame({"response": data, "response1": data})
df_original = df.copy()
mask = df.response == "timeout"
with tm.raises_chained_assignment_error():
df.response[mask] = "none"
if using_copy_on_write:
tm.assert_frame_equal(df, df_original)
else:
tm.assert_frame_equal(df, DataFrame({"response": mdata, "response1": data}))
# GH 6056
expected = DataFrame({"A": [np.nan, "bar", "bah", "foo", "bar"]})
df = DataFrame({"A": np.array(["foo", "bar", "bah", "foo", "bar"])})
with tm.raises_chained_assignment_error():
df["A"].iloc[0] = np.nan
if using_copy_on_write:
expected = DataFrame({"A": ["foo", "bar", "bah", "foo", "bar"]})
else:
expected = DataFrame({"A": [np.nan, "bar", "bah", "foo", "bar"]})
result = df.head()
tm.assert_frame_equal(result, expected)
df = DataFrame({"A": np.array(["foo", "bar", "bah", "foo", "bar"])})
with tm.raises_chained_assignment_error():
df.A.iloc[0] = np.nan
result = df.head()
tm.assert_frame_equal(result, expected)
@pytest.mark.arm_slow
def test_detect_chained_assignment(self, using_copy_on_write):
with option_context("chained_assignment", "raise"):
# work with the chain
expected = DataFrame([[-5, 1], [-6, 3]], columns=list("AB"))
df = DataFrame(
np.arange(4).reshape(2, 2), columns=list("AB"), dtype="int64"
)
df_original = df.copy()
assert df._is_copy is None
with tm.raises_chained_assignment_error():
df["A"][0] = -5
with tm.raises_chained_assignment_error():
df["A"][1] = -6
if using_copy_on_write:
tm.assert_frame_equal(df, df_original)
else:
tm.assert_frame_equal(df, expected)
@pytest.mark.arm_slow
def test_detect_chained_assignment_raises(
self, using_array_manager, using_copy_on_write, warn_copy_on_write
):
# test with the chaining
df = DataFrame(
{
"A": Series(range(2), dtype="int64"),
"B": np.array(np.arange(2, 4), dtype=np.float64),
}
)
df_original = df.copy()
assert df._is_copy is None
if using_copy_on_write:
with tm.raises_chained_assignment_error():
df["A"][0] = -5
with tm.raises_chained_assignment_error():
df["A"][1] = -6
tm.assert_frame_equal(df, df_original)
elif warn_copy_on_write:
with tm.raises_chained_assignment_error():
df["A"][0] = -5
with tm.raises_chained_assignment_error():
df["A"][1] = np.nan
elif not using_array_manager:
with pytest.raises(SettingWithCopyError, match=msg):
with tm.raises_chained_assignment_error():
df["A"][0] = -5
with pytest.raises(SettingWithCopyError, match=msg):
with tm.raises_chained_assignment_error():
df["A"][1] = np.nan
assert df["A"]._is_copy is None
else:
# INFO(ArrayManager) for ArrayManager it doesn't matter that it's
# a mixed dataframe
df["A"][0] = -5
df["A"][1] = -6
expected = DataFrame([[-5, 2], [-6, 3]], columns=list("AB"))
expected["B"] = expected["B"].astype("float64")
tm.assert_frame_equal(df, expected)
@pytest.mark.arm_slow
def test_detect_chained_assignment_fails(
self, using_copy_on_write, warn_copy_on_write
):
# Using a copy (the chain), fails
df = DataFrame(
{
"A": Series(range(2), dtype="int64"),
"B": np.array(np.arange(2, 4), dtype=np.float64),
}
)
if using_copy_on_write or warn_copy_on_write:
with tm.raises_chained_assignment_error():
df.loc[0]["A"] = -5
else:
with pytest.raises(SettingWithCopyError, match=msg):
df.loc[0]["A"] = -5
@pytest.mark.arm_slow
def test_detect_chained_assignment_doc_example(
self, using_copy_on_write, warn_copy_on_write
):
# Doc example
df = DataFrame(
{
"a": ["one", "one", "two", "three", "two", "one", "six"],
"c": Series(range(7), dtype="int64"),
}
)
assert df._is_copy is None
indexer = df.a.str.startswith("o")
if using_copy_on_write or warn_copy_on_write:
with tm.raises_chained_assignment_error():
df[indexer]["c"] = 42
else:
with pytest.raises(SettingWithCopyError, match=msg):
df[indexer]["c"] = 42
@pytest.mark.arm_slow
def test_detect_chained_assignment_object_dtype(
self, using_array_manager, using_copy_on_write, warn_copy_on_write
):
expected = DataFrame({"A": [111, "bbb", "ccc"], "B": [1, 2, 3]})
df = DataFrame(
{"A": Series(["aaa", "bbb", "ccc"], dtype=object), "B": [1, 2, 3]}
)
df_original = df.copy()
if not using_copy_on_write and not warn_copy_on_write:
with pytest.raises(SettingWithCopyError, match=msg):
df.loc[0]["A"] = 111
if using_copy_on_write:
with tm.raises_chained_assignment_error():
df["A"][0] = 111
tm.assert_frame_equal(df, df_original)
elif warn_copy_on_write:
with tm.raises_chained_assignment_error():
df["A"][0] = 111
tm.assert_frame_equal(df, expected)
elif not using_array_manager:
with pytest.raises(SettingWithCopyError, match=msg):
with tm.raises_chained_assignment_error():
df["A"][0] = 111
df.loc[0, "A"] = 111
tm.assert_frame_equal(df, expected)
else:
# INFO(ArrayManager) for ArrayManager it doesn't matter that it's
# a mixed dataframe
df["A"][0] = 111
tm.assert_frame_equal(df, expected)
@pytest.mark.arm_slow
def test_detect_chained_assignment_is_copy_pickle(self):
# gh-5475: Make sure that is_copy is picked up reconstruction
df = DataFrame({"A": [1, 2]})
assert df._is_copy is None
with tm.ensure_clean("__tmp__pickle") as path:
df.to_pickle(path)
df2 = pd.read_pickle(path)
df2["B"] = df2["A"]
df2["B"] = df2["A"]
@pytest.mark.arm_slow
def test_detect_chained_assignment_setting_entire_column(self):
# gh-5597: a spurious raise as we are setting the entire column here
df = random_text(100000)
# Always a copy
x = df.iloc[[0, 1, 2]]
assert x._is_copy is not None
x = df.iloc[[0, 1, 2, 4]]
assert x._is_copy is not None
# Explicitly copy
indexer = df.letters.apply(lambda x: len(x) > 10)
df = df.loc[indexer].copy()
assert df._is_copy is None
df["letters"] = df["letters"].apply(str.lower)
@pytest.mark.arm_slow
def test_detect_chained_assignment_implicit_take(self):
# Implicitly take
df = random_text(100000)
indexer = df.letters.apply(lambda x: len(x) > 10)
df = df.loc[indexer]
assert df._is_copy is not None
df["letters"] = df["letters"].apply(str.lower)
@pytest.mark.arm_slow
def test_detect_chained_assignment_implicit_take2(
self, using_copy_on_write, warn_copy_on_write
):
if using_copy_on_write or warn_copy_on_write:
pytest.skip("_is_copy is not always set for CoW")
# Implicitly take 2
df = random_text(100000)
indexer = df.letters.apply(lambda x: len(x) > 10)
df = df.loc[indexer]
assert df._is_copy is not None
df.loc[:, "letters"] = df["letters"].apply(str.lower)
# with the enforcement of #45333 in 2.0, the .loc[:, letters] setting
# is inplace, so df._is_copy remains non-None.
assert df._is_copy is not None
df["letters"] = df["letters"].apply(str.lower)
assert df._is_copy is None
@pytest.mark.arm_slow
def test_detect_chained_assignment_str(self):
df = random_text(100000)
indexer = df.letters.apply(lambda x: len(x) > 10)
df.loc[indexer, "letters"] = df.loc[indexer, "letters"].apply(str.lower)
@pytest.mark.arm_slow
def test_detect_chained_assignment_is_copy(self):
# an identical take, so no copy
df = DataFrame({"a": [1]}).dropna()
assert df._is_copy is None
df["a"] += 1
@pytest.mark.arm_slow
def test_detect_chained_assignment_sorting(self):
df = DataFrame(np.random.default_rng(2).standard_normal((10, 4)))
ser = df.iloc[:, 0].sort_values()
tm.assert_series_equal(ser, df.iloc[:, 0].sort_values())
tm.assert_series_equal(ser, df[0].sort_values())
@pytest.mark.arm_slow
def test_detect_chained_assignment_false_positives(self):
# see gh-6025: false positives
df = DataFrame({"column1": ["a", "a", "a"], "column2": [4, 8, 9]})
str(df)
df["column1"] = df["column1"] + "b"
str(df)
df = df[df["column2"] != 8]
str(df)
df["column1"] = df["column1"] + "c"
str(df)
@pytest.mark.arm_slow
def test_detect_chained_assignment_undefined_column(
self, using_copy_on_write, warn_copy_on_write
):
# from SO:
# https://stackoverflow.com/questions/24054495/potential-bug-setting-value-for-undefined-column-using-iloc
df = DataFrame(np.arange(0, 9), columns=["count"])
df["group"] = "b"
df_original = df.copy()
if using_copy_on_write:
with tm.raises_chained_assignment_error():
df.iloc[0:5]["group"] = "a"
tm.assert_frame_equal(df, df_original)
elif warn_copy_on_write:
with tm.raises_chained_assignment_error():
df.iloc[0:5]["group"] = "a"
else:
with pytest.raises(SettingWithCopyError, match=msg):
with tm.raises_chained_assignment_error():
df.iloc[0:5]["group"] = "a"
@pytest.mark.arm_slow
def test_detect_chained_assignment_changing_dtype(
self, using_array_manager, using_copy_on_write, warn_copy_on_write
):
# Mixed type setting but same dtype & changing dtype
df = DataFrame(
{
"A": date_range("20130101", periods=5),
"B": np.random.default_rng(2).standard_normal(5),
"C": np.arange(5, dtype="int64"),
"D": ["a", "b", "c", "d", "e"],
}
)
df_original = df.copy()
if using_copy_on_write or warn_copy_on_write:
with tm.raises_chained_assignment_error():
df.loc[2]["D"] = "foo"
with tm.raises_chained_assignment_error():
df.loc[2]["C"] = "foo"
tm.assert_frame_equal(df, df_original)
with tm.raises_chained_assignment_error(extra_warnings=(FutureWarning,)):
df["C"][2] = "foo"
if using_copy_on_write:
tm.assert_frame_equal(df, df_original)
else:
assert df.loc[2, "C"] == "foo"
else:
with pytest.raises(SettingWithCopyError, match=msg):
df.loc[2]["D"] = "foo"
with pytest.raises(SettingWithCopyError, match=msg):
df.loc[2]["C"] = "foo"
if not using_array_manager:
with pytest.raises(SettingWithCopyError, match=msg):
with tm.raises_chained_assignment_error():
df["C"][2] = "foo"
else:
# INFO(ArrayManager) for ArrayManager it doesn't matter if it's
# changing the dtype or not
df["C"][2] = "foo"
assert df.loc[2, "C"] == "foo"
def test_setting_with_copy_bug(self, using_copy_on_write, warn_copy_on_write):
# operating on a copy
df = DataFrame(
{"a": list(range(4)), "b": list("ab.."), "c": ["a", "b", np.nan, "d"]}
)
df_original = df.copy()
mask = pd.isna(df.c)
if using_copy_on_write:
with tm.raises_chained_assignment_error():
df[["c"]][mask] = df[["b"]][mask]
tm.assert_frame_equal(df, df_original)
elif warn_copy_on_write:
with tm.raises_chained_assignment_error():
df[["c"]][mask] = df[["b"]][mask]
else:
with pytest.raises(SettingWithCopyError, match=msg):
df[["c"]][mask] = df[["b"]][mask]
def test_setting_with_copy_bug_no_warning(self):
# invalid warning as we are returning a new object
# GH 8730
df1 = DataFrame({"x": Series(["a", "b", "c"]), "y": Series(["d", "e", "f"])})
df2 = df1[["x"]]
# this should not raise
df2["y"] = ["g", "h", "i"]
def test_detect_chained_assignment_warnings_errors(
self, using_copy_on_write, warn_copy_on_write
):
df = DataFrame({"A": ["aaa", "bbb", "ccc"], "B": [1, 2, 3]})
if using_copy_on_write or warn_copy_on_write:
with tm.raises_chained_assignment_error():
df.loc[0]["A"] = 111
return
with option_context("chained_assignment", "warn"):
with tm.assert_produces_warning(SettingWithCopyWarning):
df.loc[0]["A"] = 111
with option_context("chained_assignment", "raise"):
with pytest.raises(SettingWithCopyError, match=msg):
df.loc[0]["A"] = 111
@pytest.mark.parametrize("rhs", [3, DataFrame({0: [1, 2, 3, 4]})])
def test_detect_chained_assignment_warning_stacklevel(
self, rhs, using_copy_on_write, warn_copy_on_write
):
# GH#42570
df = DataFrame(np.arange(25).reshape(5, 5))
df_original = df.copy()
chained = df.loc[:3]
with option_context("chained_assignment", "warn"):
if not using_copy_on_write and not warn_copy_on_write:
with tm.assert_produces_warning(SettingWithCopyWarning) as t:
chained[2] = rhs
assert t[0].filename == __file__
else:
# INFO(CoW) no warning, and original dataframe not changed
chained[2] = rhs
tm.assert_frame_equal(df, df_original)
# TODO(ArrayManager) fast_xs with array-like scalars is not yet working
@td.skip_array_manager_not_yet_implemented
def test_chained_getitem_with_lists(self):
# GH6394
# Regression in chained getitem indexing with embedded list-like from
# 0.12
df = DataFrame({"A": 5 * [np.zeros(3)], "B": 5 * [np.ones(3)]})
expected = df["A"].iloc[2]
result = df.loc[2, "A"]
tm.assert_numpy_array_equal(result, expected)
result2 = df.iloc[2]["A"]
tm.assert_numpy_array_equal(result2, expected)
result3 = df["A"].loc[2]
tm.assert_numpy_array_equal(result3, expected)
result4 = df["A"].iloc[2]
tm.assert_numpy_array_equal(result4, expected)
def test_cache_updating(self):
# GH 4939, make sure to update the cache on setitem
df = DataFrame(
np.zeros((10, 4)),
columns=Index(list("ABCD"), dtype=object),
)
df["A"] # cache series
df.loc["Hello Friend"] = df.iloc[0]
assert "Hello Friend" in df["A"].index
assert "Hello Friend" in df["B"].index
def test_cache_updating2(self, using_copy_on_write):
# 10264
df = DataFrame(
np.zeros((5, 5), dtype="int64"),
columns=["a", "b", "c", "d", "e"],
index=range(5),
)
df["f"] = 0
df_orig = df.copy()
if using_copy_on_write:
with pytest.raises(ValueError, match="read-only"):
df.f.values[3] = 1
tm.assert_frame_equal(df, df_orig)
return
df.f.values[3] = 1
df.f.values[3] = 2
expected = DataFrame(
np.zeros((5, 6), dtype="int64"),
columns=["a", "b", "c", "d", "e", "f"],
index=range(5),
)
expected.at[3, "f"] = 2
tm.assert_frame_equal(df, expected)
expected = Series([0, 0, 0, 2, 0], name="f")
tm.assert_series_equal(df.f, expected)
def test_iloc_setitem_chained_assignment(self, using_copy_on_write):
# GH#3970
with option_context("chained_assignment", None):
df = DataFrame({"aa": range(5), "bb": [2.2] * 5})
df["cc"] = 0.0
ck = [True] * len(df)
with tm.raises_chained_assignment_error():
df["bb"].iloc[0] = 0.13
# GH#3970 this lookup used to break the chained setting to 0.15
df.iloc[ck]
with tm.raises_chained_assignment_error():
df["bb"].iloc[0] = 0.15
if not using_copy_on_write:
assert df["bb"].iloc[0] == 0.15
else:
assert df["bb"].iloc[0] == 2.2
def test_getitem_loc_assignment_slice_state(self):
# GH 13569
df = DataFrame({"a": [10, 20, 30]})
with tm.raises_chained_assignment_error():
df["a"].loc[4] = 40
tm.assert_frame_equal(df, DataFrame({"a": [10, 20, 30]}))
tm.assert_series_equal(df["a"], Series([10, 20, 30], name="a"))