Inzynierka/Lib/site-packages/pandas/tests/copy_view/test_internals.py

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2023-06-02 12:51:02 +02:00
import numpy as np
import pytest
import pandas.util._test_decorators as td
import pandas as pd
from pandas import DataFrame
import pandas._testing as tm
from pandas.tests.copy_view.util import get_array
@td.skip_array_manager_invalid_test
def test_consolidate(using_copy_on_write):
# create unconsolidated DataFrame
df = DataFrame({"a": [1, 2, 3], "b": [0.1, 0.2, 0.3]})
df["c"] = [4, 5, 6]
# take a viewing subset
subset = df[:]
# each block of subset references a block of df
assert all(blk.refs.has_reference() for blk in subset._mgr.blocks)
# consolidate the two int64 blocks
subset._consolidate_inplace()
# the float64 block still references the parent one because it still a view
assert subset._mgr.blocks[0].refs.has_reference()
# equivalent of assert np.shares_memory(df["b"].values, subset["b"].values)
# but avoids caching df["b"]
assert np.shares_memory(get_array(df, "b"), get_array(subset, "b"))
# the new consolidated int64 block does not reference another
assert not subset._mgr.blocks[1].refs.has_reference()
# the parent dataframe now also only is linked for the float column
assert not df._mgr.blocks[0].refs.has_reference()
assert df._mgr.blocks[1].refs.has_reference()
assert not df._mgr.blocks[2].refs.has_reference()
# and modifying subset still doesn't modify parent
if using_copy_on_write:
subset.iloc[0, 1] = 0.0
assert not df._mgr.blocks[1].refs.has_reference()
assert df.loc[0, "b"] == 0.1
@pytest.mark.single_cpu
@td.skip_array_manager_invalid_test
def test_switch_options():
# ensure we can switch the value of the option within one session
# (assuming data is constructed after switching)
# using the option_context to ensure we set back to global option value
# after running the test
with pd.option_context("mode.copy_on_write", False):
df = DataFrame({"a": [1, 2, 3], "b": [0.1, 0.2, 0.3]})
subset = df[:]
subset.iloc[0, 0] = 0
# df updated with CoW disabled
assert df.iloc[0, 0] == 0
pd.options.mode.copy_on_write = True
df = DataFrame({"a": [1, 2, 3], "b": [0.1, 0.2, 0.3]})
subset = df[:]
subset.iloc[0, 0] = 0
# df not updated with CoW enabled
assert df.iloc[0, 0] == 1
pd.options.mode.copy_on_write = False
df = DataFrame({"a": [1, 2, 3], "b": [0.1, 0.2, 0.3]})
subset = df[:]
subset.iloc[0, 0] = 0
# df updated with CoW disabled
assert df.iloc[0, 0] == 0
@td.skip_array_manager_invalid_test
@pytest.mark.parametrize("dtype", [np.intp, np.int8])
@pytest.mark.parametrize(
"locs, arr",
[
([0], np.array([-1, -2, -3])),
([1], np.array([-1, -2, -3])),
([5], np.array([-1, -2, -3])),
([0, 1], np.array([[-1, -2, -3], [-4, -5, -6]]).T),
([0, 2], np.array([[-1, -2, -3], [-4, -5, -6]]).T),
([0, 1, 2], np.array([[-1, -2, -3], [-4, -5, -6], [-4, -5, -6]]).T),
([1, 2], np.array([[-1, -2, -3], [-4, -5, -6]]).T),
([1, 3], np.array([[-1, -2, -3], [-4, -5, -6]]).T),
([1, 3], np.array([[-1, -2, -3], [-4, -5, -6]]).T),
],
)
def test_iset_splits_blocks_inplace(using_copy_on_write, locs, arr, dtype):
# Nothing currently calls iset with
# more than 1 loc with inplace=True (only happens with inplace=False)
# but ensure that it works
df = DataFrame(
{
"a": [1, 2, 3],
"b": [4, 5, 6],
"c": [7, 8, 9],
"d": [10, 11, 12],
"e": [13, 14, 15],
"f": ["a", "b", "c"],
},
)
arr = arr.astype(dtype)
df_orig = df.copy()
df2 = df.copy(deep=None) # Trigger a CoW (if enabled, otherwise makes copy)
df2._mgr.iset(locs, arr, inplace=True)
tm.assert_frame_equal(df, df_orig)
if using_copy_on_write:
for i, col in enumerate(df.columns):
if i not in locs:
assert np.shares_memory(get_array(df, col), get_array(df2, col))
else:
for col in df.columns:
assert not np.shares_memory(get_array(df, col), get_array(df2, col))