ENH: Add xlsb auto detection to read_excel and respect default options (#38710)

Author: lithomas1

doc/source/whatsnew/v1.3.0.rst

@@ -51,6 +51,7 @@ Other enhancements
 - :func:`pandas.read_sql_query` now accepts a ``dtype`` argument to cast the columnar data from the SQL database based on user input (:issue:`10285`)
 - Improved integer type mapping from pandas to SQLAlchemy when using :meth:`DataFrame.to_sql` (:issue:`35076`)
 - :func:`to_numeric` now supports downcasting of nullable ``ExtensionDtype`` objects (:issue:`33013`)
+- :func:`pandas.read_excel` can now auto detect .xlsb files (:issue:`35416`)
 
 .. ---------------------------------------------------------------------------
 
@@ -270,7 +271,7 @@ I/O
   for subclasses of ``DataFrame`` or ``Series`` (:issue:`33748`).
 - Bug in :func:`json_normalize` resulting in the first element of a generator object not being included in the returned ``DataFrame`` (:issue:`35923`)
 - Bug in :func:`read_excel` forward filling :class:`MultiIndex` names with multiple header and index columns specified (:issue:`34673`)
-
+- :func:`pandas.read_excel` now respects :func:``pandas.set_option`` (:issue:`34252`)
 
 Period
 ^^^^^^

pandas/core/config_init.py

@@ -524,15 +524,15 @@ def use_inf_as_na_cb(key):
         "reader",
         "auto",
         reader_engine_doc.format(ext="xls", others=", ".join(_xls_options)),
-        validator=str,
+        validator=is_one_of_factory(_xls_options + ["auto"]),
     )
 
 with cf.config_prefix("io.excel.xlsm"):
     cf.register_option(
         "reader",
         "auto",
         reader_engine_doc.format(ext="xlsm", others=", ".join(_xlsm_options)),
-        validator=str,
+        validator=is_one_of_factory(_xlsm_options + ["auto"]),
     )
 
 
@@ -541,7 +541,7 @@ def use_inf_as_na_cb(key):
         "reader",
         "auto",
         reader_engine_doc.format(ext="xlsx", others=", ".join(_xlsx_options)),
-        validator=str,
+        validator=is_one_of_factory(_xlsx_options + ["auto"]),
     )
 
 
@@ -550,15 +550,15 @@ def use_inf_as_na_cb(key):
         "reader",
         "auto",
         reader_engine_doc.format(ext="ods", others=", ".join(_ods_options)),
-        validator=str,
+        validator=is_one_of_factory(_ods_options + ["auto"]),
     )
 
 with cf.config_prefix("io.excel.xlsb"):
     cf.register_option(
         "reader",
         "auto",
         reader_engine_doc.format(ext="xlsb", others=", ".join(_xlsb_options)),
-        validator=str,
+        validator=is_one_of_factory(_xlsb_options + ["auto"]),
     )
 
 # Set up the io.excel specific writer configuration.

pandas/io/excel/_base.py

@@ -25,7 +25,7 @@
 from pandas.io.common import IOHandles, get_handle, stringify_path, validate_header_arg
 from pandas.io.excel._util import (
     fill_mi_header,
-    get_default_writer,
+    get_default_engine,
     get_writer,
     maybe_convert_usecols,
     pop_header_name,
@@ -123,6 +123,10 @@
          then `odf <https://pypi.org/project/odfpy/>`_ will be used.
        - Otherwise if ``path_or_buffer`` is an xls format,
          ``xlrd`` will be used.
+       - Otherwise if ``path_or_buffer`` is in xlsb format,
+         ``pyxlsb`` will be used.
+
+         .. versionadded:: 1.3.0
        - Otherwise if `openpyxl <https://pypi.org/project/openpyxl/>`_ is installed,
          then ``openpyxl`` will be used.
        - Otherwise if ``xlrd >= 2.0`` is installed, a ``ValueError`` will be raised.
@@ -707,7 +711,7 @@ def __new__(cls, path, engine=None, **kwargs):
                 try:
                     engine = config.get_option(f"io.excel.{ext}.writer", silent=True)
                     if engine == "auto":
-                        engine = get_default_writer(ext)
+                        engine = get_default_engine(ext, mode="writer")
                 except KeyError as err:
                     raise ValueError(f"No engine for filetype: '{ext}'") from err
 
@@ -1009,6 +1013,10 @@ class ExcelFile:
              then `odf <https://pypi.org/project/odfpy/>`_ will be used.
            - Otherwise if ``path_or_buffer`` is an xls format,
              ``xlrd`` will be used.
+           - Otherwise if ``path_or_buffer`` is in xlsb format,
+             `pyxlsb <https://pypi.org/project/pyxlsb/>`_ will be used.
+
+           .. versionadded:: 1.3.0
            - Otherwise if `openpyxl <https://pypi.org/project/openpyxl/>`_ is installed,
              then ``openpyxl`` will be used.
            - Otherwise if ``xlrd >= 2.0`` is installed, a ``ValueError`` will be raised.
@@ -1065,21 +1073,10 @@ def __init__(
             )
 
         if engine is None:
-            if ext == "ods":
-                engine = "odf"
-            elif ext == "xls":
-                engine = "xlrd"
-            else:
-                # GH 35029 - Prefer openpyxl except for xls files
-                if (
-                    import_optional_dependency(
-                        "openpyxl", raise_on_missing=False, on_version="ignore"
-                    )
-                    is not None
-                ):
-                    engine = "openpyxl"
-                else:
-                    engine = "xlrd"
+            # ext will always be valid, otherwise inspect_excel_format would raise
+            engine = config.get_option(f"io.excel.{ext}.reader", silent=True)
+            if engine == "auto":
+                engine = get_default_engine(ext, mode="reader")
 
         if engine == "xlrd" and ext != "xls" and xlrd_version is not None:
             if xlrd_version >= "2":
@@ -1107,7 +1104,6 @@ def __init__(
                     FutureWarning,
                     stacklevel=stacklevel,
                 )
-        assert engine in self._engines, f"Engine {engine} not recognized"
 
         self.engine = engine
         self.storage_options = storage_options

pandas/io/excel/_util.py

@@ -23,32 +23,61 @@ def register_writer(klass):
     _writers[engine_name] = klass
 
 
-def get_default_writer(ext):
+def get_default_engine(ext, mode="reader"):
     """
-    Return the default writer for the given extension.
+    Return the default reader/writer for the given extension.
 
     Parameters
     ----------
     ext : str
         The excel file extension for which to get the default engine.
+    mode : str {'reader', 'writer'}
+        Whether to get the default engine for reading or writing.
+        Either 'reader' or 'writer'
 
     Returns
     -------
     str
         The default engine for the extension.
     """
+    _default_readers = {
+        "xlsx": "openpyxl",
+        "xlsm": "openpyxl",
+        "xlsb": "pyxlsb",
+        "xls": "xlrd",
+        "ods": "odf",
+    }
     _default_writers = {
         "xlsx": "openpyxl",
         "xlsm": "openpyxl",
+        "xlsb": "pyxlsb",
         "xls": "xlwt",
         "ods": "odf",
     }
-    xlsxwriter = import_optional_dependency(
-        "xlsxwriter", raise_on_missing=False, on_version="warn"
-    )
-    if xlsxwriter:
-        _default_writers["xlsx"] = "xlsxwriter"
-    return _default_writers[ext]
+    assert mode in ["reader", "writer"]
+    if mode == "writer":
+        # Prefer xlsxwriter over openpyxl if installed
+        xlsxwriter = import_optional_dependency(
+            "xlsxwriter", raise_on_missing=False, on_version="warn"
+        )
+        if xlsxwriter:
+            _default_writers["xlsx"] = "xlsxwriter"
+        return _default_writers[ext]
+    else:
+        if (
+            import_optional_dependency(
+                "openpyxl", raise_on_missing=False, on_version="ignore"
+            )
+            is None
+            and import_optional_dependency(
+                "xlrd", raise_on_missing=False, on_version="ignore"
+            )
+            is not None
+        ):
+            # if no openpyxl but xlrd installed, return xlrd
+            # the version is handled elsewhere
+            _default_readers["xlsx"] = "xlrd"
+        return _default_readers[ext]
 
 
 def get_writer(engine_name):

pandas/tests/io/excel/test_readers.py

@@ -1234,8 +1234,6 @@ def test_excel_read_binary(self, engine, read_ext):
 
     def test_excel_read_binary_via_read_excel(self, read_ext, engine):
         # GH 38424
-        if read_ext == ".xlsb" and engine == "pyxlsb":
-            pytest.xfail("GH 38667 - should default to pyxlsb but doesn't")
         with open("test1" + read_ext, "rb") as f:
             result = pd.read_excel(f)
         expected = pd.read_excel("test1" + read_ext, engine=engine)
@@ -1282,3 +1280,9 @@ def test_read_datetime_multiindex(self, engine, read_ext):
         expected = DataFrame([], columns=expected_column_index)
 
         tm.assert_frame_equal(expected, actual)
+
+    def test_engine_invalid_option(self, read_ext):
+        # read_ext includes the '.' hence the weird formatting
+        with pytest.raises(ValueError, match="Value must be one of *"):
+            with pd.option_context(f"io.excel{read_ext}.reader", "abc"):
+                pass