From 217413ad6697d31edad9b32fc7b5da019fcdef44 Mon Sep 17 00:00:00 2001 From: Simon Hawkins Date: Wed, 6 May 2020 16:20:47 +0100 Subject: [PATCH] Backport PR #32905 on branch 1.0.x (Fix to _get_nearest_indexer for pydata/xarray#3751) (#34025) Co-authored-by: Spencer Clark --- doc/source/whatsnew/v1.0.4.rst | 1 + environment.yml | 1 + pandas/core/indexes/base.py | 9 +++++---- pandas/tests/test_downstream.py | 15 +++++++++++++++ requirements-dev.txt | 1 + 5 files changed, 23 insertions(+), 4 deletions(-) diff --git a/doc/source/whatsnew/v1.0.4.rst b/doc/source/whatsnew/v1.0.4.rst index 80f8976826bc8..2852b3b4fe92c 100644 --- a/doc/source/whatsnew/v1.0.4.rst +++ b/doc/source/whatsnew/v1.0.4.rst @@ -21,6 +21,7 @@ Fixed regressions - Fix performance regression in ``memory_usage(deep=True)`` for object dtype (:issue:`33012`) - Bug where :meth:`Categorical.replace` would replace with ``NaN`` whenever the new value and replacement value were equal (:issue:`33288`) - Bug where an ordered :class:`Categorical` containing only ``NaN`` values would raise rather than returning ``NaN`` when taking the minimum or maximum (:issue:`33450`) +- Fix to preserve the ability to index with the "nearest" method with xarray's CFTimeIndex, an :class:`Index` subclass (`pydata/xarray#3751 `_, :issue:`32905`). - .. _whatsnew_104.bug_fixes: diff --git a/environment.yml b/environment.yml index 3c7aed32af3f8..ea15bf1bffe1f 100644 --- a/environment.yml +++ b/environment.yml @@ -102,6 +102,7 @@ dependencies: - s3fs # pandas.read_csv... when using 's3://...' path - sqlalchemy # pandas.read_sql, DataFrame.to_sql - xarray # DataFrame.to_xarray + - cftime # Needed for downstream xarray.CFTimeIndex test - pyreadstat # pandas.read_spss - tabulate>=0.8.3 # DataFrame.to_markdown - pip: diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py index 38f8521bfa2d4..5ff8f590e78aa 100644 --- a/pandas/core/indexes/base.py +++ b/pandas/core/indexes/base.py @@ -2817,8 +2817,9 @@ def _get_nearest_indexer(self, target, limit, tolerance): left_indexer = self.get_indexer(target, "pad", limit=limit) right_indexer = self.get_indexer(target, "backfill", limit=limit) - left_distances = np.abs(self[left_indexer] - target) - right_distances = np.abs(self[right_indexer] - target) + target_values = target._values + left_distances = np.abs(self._values[left_indexer] - target_values) + right_distances = np.abs(self._values[right_indexer] - target_values) op = operator.lt if self.is_monotonic_increasing else operator.le indexer = np.where( @@ -2827,11 +2828,11 @@ def _get_nearest_indexer(self, target, limit, tolerance): right_indexer, ) if tolerance is not None: - indexer = self._filter_indexer_tolerance(target, indexer, tolerance) + indexer = self._filter_indexer_tolerance(target_values, indexer, tolerance) return indexer def _filter_indexer_tolerance(self, target, indexer, tolerance): - distance = abs(self.values[indexer] - target) + distance = abs(self._values[indexer] - target) indexer = np.where(distance <= tolerance, indexer, -1) return indexer diff --git a/pandas/tests/test_downstream.py b/pandas/tests/test_downstream.py index d4d7803a724e2..9f473d1ad4df6 100644 --- a/pandas/tests/test_downstream.py +++ b/pandas/tests/test_downstream.py @@ -8,6 +8,8 @@ import numpy as np # noqa import pytest +import pandas.util._test_decorators as td + from pandas import DataFrame, Series import pandas._testing as tm @@ -47,6 +49,19 @@ def test_xarray(df): assert df.to_xarray() is not None +@td.skip_if_no("cftime") +@td.skip_if_no("xarray", "0.10.4") +def test_xarray_cftimeindex_nearest(): + # https://github.com/pydata/xarray/issues/3751 + import cftime + import xarray + + times = xarray.cftime_range("0001", periods=2) + result = times.get_loc(cftime.DatetimeGregorian(2000, 1, 1), method="nearest") + expected = 1 + assert result == expected + + def test_oo_optimizable(): # GH 21071 subprocess.check_call([sys.executable, "-OO", "-c", "import pandas"]) diff --git a/requirements-dev.txt b/requirements-dev.txt index 3089b96d26780..0b8236c4fd1d2 100644 --- a/requirements-dev.txt +++ b/requirements-dev.txt @@ -69,6 +69,7 @@ tables>=3.4.2 s3fs sqlalchemy xarray +cftime pyreadstat tabulate>=0.8.3 git+https://github.com/pandas-dev/pydata-sphinx-theme.git@master \ No newline at end of file