Merge remote-tracking branch 'upstream/main' into pyarrow-timestamp-map

Author: KevsterAmp

.github/workflows/unit-tests.yml

@@ -71,7 +71,7 @@ jobs:
             # It will be temporarily activated during tests with locale.setlocale
             extra_loc: "zh_CN"
             platform: ubuntu-24.04
-          - name: "Past no infer strings"
+          - name: "PANDAS_FUTURE_INFER_STRING=0"
             env_file: actions-312.yaml
             pandas_future_infer_string: "0"
             platform: ubuntu-24.04

.github/workflows/wheels.yml

@@ -162,7 +162,7 @@ jobs:
         run: echo "sdist_name=$(cd ./dist && ls -d */)" >> "$GITHUB_ENV"
 
       - name: Build wheels
-        uses: pypa/cibuildwheel@v2.23.3
+        uses: pypa/cibuildwheel@v3.1.3
         with:
          package-dir: ./dist/${{ startsWith(matrix.buildplat[1], 'macosx') && env.sdist_name || needs.build_sdist.outputs.sdist_file }}
         env:

.pre-commit-config.yaml

@@ -19,7 +19,7 @@ ci:
     skip: [pyright, mypy]
 repos:
 -   repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.12.2
+    rev: v0.12.7
     hooks:
     -   id: ruff
         args: [--exit-non-zero-on-fix]
@@ -95,14 +95,14 @@ repos:
     - id: sphinx-lint
       args: ["--enable", "all", "--disable", "line-too-long"]
 -   repo: https://github.com/pre-commit/mirrors-clang-format
-    rev: v20.1.7
+    rev: v20.1.8
     hooks:
     - id: clang-format
       files: ^pandas/_libs/src|^pandas/_libs/include
       args: [-i]
       types_or: [c, c++]
 -   repo: https://github.com/trim21/pre-commit-mirror-meson
-    rev: v1.8.2
+    rev: v1.8.3
     hooks:
     - id: meson-fmt
       args: ['--inplace']

README.md

@@ -115,7 +115,7 @@ details, see the commit logs at https://github.com/pandas-dev/pandas.
 ## Dependencies
 - [NumPy - Adds support for large, multi-dimensional arrays, matrices and high-level mathematical functions to operate on these arrays](https://www.numpy.org)
 - [python-dateutil - Provides powerful extensions to the standard datetime module](https://dateutil.readthedocs.io/en/stable/index.html)
-- [pytz - Brings the Olson tz database into Python which allows accurate and cross platform timezone calculations](https://github.com/stub42/pytz)
+- [tzdata - Provides an IANA time zone database](https://tzdata.readthedocs.io/en/latest/)
 
 See the [full installation instructions](https://pandas.pydata.org/pandas-docs/stable/install.html#dependencies) for minimum supported versions of required, recommended and optional dependencies.
 

ci/code_checks.sh

@@ -58,9 +58,7 @@ if [[ -z "$CHECK" || "$CHECK" == "doctests" ]]; then
 
     MSG='Python and Cython Doctests' ; echo "$MSG"
     python -c 'import pandas as pd; pd.test(run_doctests=True)'
-    # TEMP don't let doctests fail the build until all string dtype changes are fixed
-    # RET=$(($RET + $?)) ; echo "$MSG" "DONE"
-    echo "$MSG" "DONE"
+    RET=$(($RET + $?)) ; echo "$MSG" "DONE"
 
 fi
 

ci/deps/actions-311-downstream_compat.yaml

@@ -50,8 +50,7 @@ dependencies:
   - pytz>=2023.4
   - pyxlsb>=1.0.10
   - s3fs>=2023.12.2
-  # TEMP upper pin for scipy (https://github.com/statsmodels/statsmodels/issues/9584)
-  - scipy>=1.12.0,<1.16
+  - scipy>=1.12.0
   - sqlalchemy>=2.0.0
   - tabulate>=0.9.0
   - xarray>=2024.1.1

doc/source/development/contributing_documentation.rst

@@ -157,6 +157,11 @@ If you want to do a full clean build, do::
     python make.py clean
     python make.py html
 
+.. tip::
+  If ``python make.py html`` exits with an error status,
+  try running the command ``python make.py html --num-jobs=1``
+  to identify the cause of the error.
+
 You can tell ``make.py`` to compile only a single section of the docs, greatly
 reducing the turn-around time for checking your changes.
 

doc/source/user_guide/indexing.rst

@@ -1732,3 +1732,49 @@ Why does assignment fail when using chained indexing?
 This means that chained indexing will never work.
 See :ref:`this section <copy_on_write_chained_assignment>`
 for more context.
+
+.. _indexing.series_assignment:
+
+Series Assignment and Index Alignment
+-------------------------------------
+
+When assigning a Series to a DataFrame column, pandas performs automatic alignment
+based on index labels. This is a fundamental behavior that can be surprising to
+new users who might expect positional assignment.
+
+Key Points:
+~~~~~~~~~~~
+
+* Series values are matched to DataFrame rows by index label
+* Position/order in the Series doesn't matter
+* Missing index labels result in NaN values
+* This behavior is consistent across df[col] = series and df.loc[:, col] = series
+
+Examples:
+.. ipython:: python
+
+   import pandas as pd
+
+   # Create a DataFrame
+   df = pd.DataFrame({'values': [1, 2, 3]}, index=['x', 'y', 'z'])
+
+   # Series with matching indices (different order)
+   s1 = pd.Series([10, 20, 30], index=['z', 'x', 'y'])
+   df['aligned'] = s1  # Aligns by index, not position
+   print(df)
+
+   # Series with partial index match
+   s2 = pd.Series([100, 200], index=['x', 'z'])
+   df['partial'] = s2  # Missing 'y' gets NaN
+   print(df)
+
+   # Series with non-matching indices
+   s3 = pd.Series([1000, 2000], index=['a', 'b'])
+   df['nomatch'] = s3  # All values become NaN
+   print(df)
+
+
+   #Avoiding Confusion:
+   #If you want positional assignment instead of index alignment:
+   # reset the Series index to match DataFrame index
+   df['s1_values'] = s1.reindex(df.index)

doc/source/user_guide/migration-3-strings.rst

@@ -118,12 +118,17 @@ through the ``str`` accessor will work the same:
 Overview of behavior differences and how to address them
 ---------------------------------------------------------
 
-The dtype is no longer object dtype
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The dtype is no longer a numpy "object" dtype
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 When inferring or reading string data, the data type of the resulting DataFrame
 column or Series will silently start being the new ``"str"`` dtype instead of
-``"object"`` dtype, and this can have some impact on your code.
+the numpy ``"object"`` dtype, and this can have some impact on your code.
+
+The new string dtype is a pandas data type ("extension dtype"), and no longer a
+numpy ``np.dtype`` instance. Therefore, passing the dtype of a string column to
+numpy functions will no longer work (e.g. passing it to a ``dtype=`` argument
+of a numpy function, or using ``np.issubdtype`` to check the dtype).
 
 Checking the dtype
 ^^^^^^^^^^^^^^^^^^

doc/source/whatsnew/index.rst

@@ -24,6 +24,7 @@ Version 2.3
 .. toctree::
    :maxdepth: 2
 
+   v2.3.2
    v2.3.1
    v2.3.0