From 37261cef1443fee7c3bd1754ec495ab5e79c0fe2 Mon Sep 17 00:00:00 2001
From: Thomas Li <thomasli1234567890@gmail.com>
Date: Mon, 6 Sep 2021 10:12:40 -0700
Subject: [PATCH 1/9] DEPR: squeeze argument in read_csv/read_table/read_excel

---
 doc/source/whatsnew/v1.4.0.rst                |  1 +
 pandas/io/excel/_base.py                      | 77 +++++++++++--------
 pandas/io/parsers/base_parser.py              |  2 +-
 pandas/io/parsers/c_parser_wrapper.py         |  1 -
 pandas/io/parsers/readers.py                  | 23 ++++--
 pandas/tests/io/excel/test_readers.py         | 27 ++++---
 .../io/parser/common/test_common_basic.py     | 26 +++++--
 7 files changed, 100 insertions(+), 57 deletions(-)

diff --git a/doc/source/whatsnew/v1.4.0.rst b/doc/source/whatsnew/v1.4.0.rst
index 3b9ddf8138689..de20c200ba1bc 100644
--- a/doc/source/whatsnew/v1.4.0.rst
+++ b/doc/source/whatsnew/v1.4.0.rst
@@ -275,6 +275,7 @@ Other Deprecations
 - Deprecated :meth:`Index.reindex` with a non-unique index (:issue:`42568`)
 - Deprecated :meth:`.Styler.render` in favour of :meth:`.Styler.to_html` (:issue:`42140`)
 - Deprecated passing in a string column label into ``times`` in :meth:`DataFrame.ewm` (:issue:`43265`)
+- Deprecated the ``squeeze`` argument to :meth:`read_csv`, :meth:`read_table`, and :meth:`read_excel`. Users should squeeze the DataFrame afterwards with ``.squeeze("columns")`` instead. (:issue:`43242`)
 
 .. ---------------------------------------------------------------------------
 
diff --git a/pandas/io/excel/_base.py b/pandas/io/excel/_base.py
index 52d1e1c83d3e6..b1a2a3824efc9 100644
--- a/pandas/io/excel/_base.py
+++ b/pandas/io/excel/_base.py
@@ -121,6 +121,9 @@
     Returns a subset of the columns according to behavior above.
 squeeze : bool, default False
     If the parsed data only contains one column then return a Series.
+    .. deprecated:: 1.4.0
+        Append ``.squeeze("columns")`` to the call to ``read_excel`` to squeeze
+        the data.
 dtype : Type name or dict of column -> type, default None
     Data type for data or columns. E.g. {'a': np.float64, 'b': np.int32}
     Use `object` to preserve data as stored in Excel and not interpret dtype.
@@ -337,7 +340,7 @@ def read_excel(
     names=None,
     index_col=None,
     usecols=None,
-    squeeze=False,
+    squeeze=None,
     dtype: DtypeArg | None = None,
     engine=None,
     converters=None,
@@ -481,7 +484,7 @@ def parse(
         names=None,
         index_col=None,
         usecols=None,
-        squeeze=False,
+        squeeze=None,
         dtype: DtypeArg | None = None,
         true_values=None,
         false_values=None,
@@ -598,41 +601,49 @@ def parse(
                                 data[row][col] = last
                             else:
                                 last = data[row][col]
-
+            future_warnings = []
             # GH 12292 : error when read one empty column from excel file
             try:
-                parser = TextParser(
-                    data,
-                    names=names,
-                    header=header,
-                    index_col=index_col,
-                    has_index_names=has_index_names,
-                    squeeze=squeeze,
-                    dtype=dtype,
-                    true_values=true_values,
-                    false_values=false_values,
-                    skiprows=skiprows,
-                    nrows=nrows,
-                    na_values=na_values,
-                    skip_blank_lines=False,  # GH 39808
-                    parse_dates=parse_dates,
-                    date_parser=date_parser,
-                    thousands=thousands,
-                    comment=comment,
-                    skipfooter=skipfooter,
-                    usecols=usecols,
-                    mangle_dupe_cols=mangle_dupe_cols,
-                    **kwds,
-                )
+                # Gotta catch deprecation warnings to raise at correct stacklevel :(
+                with warnings.catch_warnings(record=True) as w:
+                    parser = TextParser(
+                        data,
+                        names=names,
+                        header=header,
+                        index_col=index_col,
+                        has_index_names=has_index_names,
+                        squeeze=squeeze,
+                        dtype=dtype,
+                        true_values=true_values,
+                        false_values=false_values,
+                        skiprows=skiprows,
+                        nrows=nrows,
+                        na_values=na_values,
+                        skip_blank_lines=False,  # GH 39808
+                        parse_dates=parse_dates,
+                        date_parser=date_parser,
+                        thousands=thousands,
+                        comment=comment,
+                        skipfooter=skipfooter,
+                        usecols=usecols,
+                        mangle_dupe_cols=mangle_dupe_cols,
+                        **kwds,
+                    )
 
-                output[asheetname] = parser.read(nrows=nrows)
+                    output[asheetname] = parser.read(nrows=nrows)
 
-                if not squeeze or isinstance(output[asheetname], DataFrame):
-                    if header_names:
-                        output[asheetname].columns = output[
-                            asheetname
-                        ].columns.set_names(header_names)
+                    if not squeeze or isinstance(output[asheetname], DataFrame):
+                        if header_names:
+                            output[asheetname].columns = output[
+                                asheetname
+                            ].columns.set_names(header_names)
 
+                    # Record warning messages, can't raise here since it would be
+                    # suppressed again
+                    for warning in w:
+                        future_warnings.append(str(warning.message))
+                for warning in future_warnings:
+                    warnings.warn(warning, FutureWarning, stacklevel=5)
             except EmptyDataError:
                 # No Data, return an empty DataFrame
                 output[asheetname] = DataFrame()
@@ -1243,7 +1254,7 @@ def parse(
         names=None,
         index_col=None,
         usecols=None,
-        squeeze=False,
+        squeeze=None,
         converters=None,
         true_values=None,
         false_values=None,
diff --git a/pandas/io/parsers/base_parser.py b/pandas/io/parsers/base_parser.py
index c7516a2df50f6..983f7b6a20a48 100644
--- a/pandas/io/parsers/base_parser.py
+++ b/pandas/io/parsers/base_parser.py
@@ -104,7 +104,7 @@
     "chunksize": None,
     "verbose": False,
     "encoding": None,
-    "squeeze": False,
+    "squeeze": None,
     "compression": None,
     "mangle_dupe_cols": True,
     "infer_datetime_format": False,
diff --git a/pandas/io/parsers/c_parser_wrapper.py b/pandas/io/parsers/c_parser_wrapper.py
index 57ae61548d8d0..7998fe57b58c8 100644
--- a/pandas/io/parsers/c_parser_wrapper.py
+++ b/pandas/io/parsers/c_parser_wrapper.py
@@ -33,7 +33,6 @@ class CParserWrapper(ParserBase):
     def __init__(self, src: FilePathOrBuffer, **kwds):
         self.kwds = kwds
         kwds = kwds.copy()
-
         ParserBase.__init__(self, kwds)
 
         self.low_memory = kwds.pop("low_memory", False)
diff --git a/pandas/io/parsers/readers.py b/pandas/io/parsers/readers.py
index b4a7a4f5e9325..0782da49dc939 100644
--- a/pandas/io/parsers/readers.py
+++ b/pandas/io/parsers/readers.py
@@ -131,6 +131,10 @@
     parsing time and lower memory usage.
 squeeze : bool, default False
     If the parsed data only contains one column then return a Series.
+
+    .. deprecated:: 1.4.0
+        Append ``.squeeze("columns")`` to the call to ``read_csv`` to squeeze
+        the data.
 prefix : str, optional
     Prefix to add to column numbers when no header, e.g. 'X' for X0, X1, ...
 mangle_dupe_cols : bool, default True
@@ -439,7 +443,11 @@
     "low_memory",
 }
 
-_deprecated_defaults: dict[str, Any] = {"error_bad_lines": None, "warn_bad_lines": None}
+_deprecated_defaults: dict[str, Any] = {
+    "error_bad_lines": None,
+    "warn_bad_lines": None,
+    "squeeze": None,
+}
 
 
 def validate_integer(name, val, min_val=0):
@@ -552,7 +560,7 @@ def read_csv(
     names=lib.no_default,
     index_col=None,
     usecols=None,
-    squeeze=False,
+    squeeze=None,
     prefix=lib.no_default,
     mangle_dupe_cols=True,
     # General Parsing Configuration
@@ -650,7 +658,7 @@ def read_table(
     names=lib.no_default,
     index_col=None,
     usecols=None,
-    squeeze=False,
+    squeeze=None,
     prefix=lib.no_default,
     mangle_dupe_cols=True,
     # General Parsing Configuration
@@ -867,11 +875,12 @@ def __init__(self, f, engine=None, **kwds):
 
         self.chunksize = options.pop("chunksize", None)
         self.nrows = options.pop("nrows", None)
-        self.squeeze = options.pop("squeeze", False)
 
         self._check_file_or_buffer(f, engine)
         self.options, self.engine = self._clean_options(options, engine)
 
+        self.squeeze = self.options.pop("squeeze", False)
+
         if "has_index_names" in kwds:
             self.options["has_index_names"] = kwds["has_index_names"]
 
@@ -1100,6 +1109,10 @@ def _clean_options(self, options, engine):
         result["na_values"] = na_values
         result["na_fvalues"] = na_fvalues
         result["skiprows"] = skiprows
+        # Default for squeeze is none since we need to check
+        # if user sets it, we set to False since behavior is
+        # equivlent
+        result["squeeze"] = False if options["squeeze"] is None else options["squeeze"]
 
         return result, engine
 
@@ -1149,7 +1162,7 @@ def read(self, nrows=None):
             self._currow += new_rows
 
         if self.squeeze and len(df.columns) == 1:
-            return df[df.columns[0]].copy()
+            return df.squeeze("columns").copy()
         return df
 
     def get_chunk(self, size=None):
diff --git a/pandas/tests/io/excel/test_readers.py b/pandas/tests/io/excel/test_readers.py
index f999733192725..657e64bd01809 100644
--- a/pandas/tests/io/excel/test_readers.py
+++ b/pandas/tests/io/excel/test_readers.py
@@ -1194,18 +1194,25 @@ def test_read_excel_squeeze(self, read_ext):
         # GH 12157
         f = "test_squeeze" + read_ext
 
-        actual = pd.read_excel(f, sheet_name="two_columns", index_col=0, squeeze=True)
-        expected = Series([2, 3, 4], [4, 5, 6], name="b")
-        expected.index.name = "a"
-        tm.assert_series_equal(actual, expected)
+        with tm.assert_produces_warning(
+            FutureWarning,
+            match="The squeeze argument has been deprecated "
+            "and will be removed in a future version.\n\n",
+        ):
+            actual = pd.read_excel(
+                f, sheet_name="two_columns", index_col=0, squeeze=True
+            )
+            expected = Series([2, 3, 4], [4, 5, 6], name="b")
+            expected.index.name = "a"
+            tm.assert_series_equal(actual, expected)
 
-        actual = pd.read_excel(f, sheet_name="two_columns", squeeze=True)
-        expected = DataFrame({"a": [4, 5, 6], "b": [2, 3, 4]})
-        tm.assert_frame_equal(actual, expected)
+            actual = pd.read_excel(f, sheet_name="two_columns", squeeze=True)
+            expected = DataFrame({"a": [4, 5, 6], "b": [2, 3, 4]})
+            tm.assert_frame_equal(actual, expected)
 
-        actual = pd.read_excel(f, sheet_name="one_column", squeeze=True)
-        expected = Series([1, 2, 3], name="a")
-        tm.assert_series_equal(actual, expected)
+            actual = pd.read_excel(f, sheet_name="one_column", squeeze=True)
+            expected = Series([1, 2, 3], name="a")
+            tm.assert_series_equal(actual, expected)
 
     def test_deprecated_kwargs(self, read_ext):
         with tm.assert_produces_warning(FutureWarning, raise_on_extra_warnings=False):
diff --git a/pandas/tests/io/parser/common/test_common_basic.py b/pandas/tests/io/parser/common/test_common_basic.py
index 841df0ea7e470..8d517f04f3219 100644
--- a/pandas/tests/io/parser/common/test_common_basic.py
+++ b/pandas/tests/io/parser/common/test_common_basic.py
@@ -128,7 +128,8 @@ def test_1000_sep(all_parsers):
     tm.assert_frame_equal(result, expected)
 
 
-def test_squeeze(all_parsers):
+@pytest.mark.parametrize("squeeze", [True, False])
+def test_squeeze(all_parsers, squeeze):
     data = """\
 a,1
 b,2
@@ -138,13 +139,24 @@ def test_squeeze(all_parsers):
     index = Index(["a", "b", "c"], name=0)
     expected = Series([1, 2, 3], name=1, index=index)
 
-    result = parser.read_csv(StringIO(data), index_col=0, header=None, squeeze=True)
-    tm.assert_series_equal(result, expected)
+    with tm.assert_produces_warning(
+        FutureWarning,
+        match="The squeeze argument has been deprecated "
+        "and will be removed in a future version.\n\n",
+    ):
+        result = parser.read_csv(
+            StringIO(data), index_col=0, header=None, squeeze=squeeze
+        )
+        if not squeeze:
+            expected = DataFrame(expected)
+            tm.assert_frame_equal(result, expected)
+        else:
+            tm.assert_series_equal(result, expected)
 
-    # see gh-8217
-    #
-    # Series should not be a view.
-    assert not result._is_view
+            # see gh-8217
+            #
+            # Series should not be a view.
+            assert not result._is_view
 
 
 @xfail_pyarrow

From 41ce64a5e82579d93bed4c6a3902675181643588 Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Mon, 6 Sep 2021 11:53:23 -0700
Subject: [PATCH 2/9] doc

---
 doc/source/user_guide/io.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/doc/source/user_guide/io.rst b/doc/source/user_guide/io.rst
index 4c7b13bcf989f..ab9dec2365971 100644
--- a/doc/source/user_guide/io.rst
+++ b/doc/source/user_guide/io.rst
@@ -1208,6 +1208,10 @@ Returning Series
 Using the ``squeeze`` keyword, the parser will return output with a single column
 as a ``Series``:
 
+.. deprecated:: 1.4.0
+   Users should append ``.squeeze("columns")`` to the DataFrame returned by
+   ``read_csv`` instead.
+
 .. ipython:: python
    :suppress:
 

From d6b977b5240d1acb4cb5da31cfc4f08537976711 Mon Sep 17 00:00:00 2001
From: Thomas Li <thomasli1234567890@gmail.com>
Date: Wed, 8 Sep 2021 16:17:46 -0700
Subject: [PATCH 3/9] Fixes

---
 pandas/io/excel/_base.py                      | 68 ++++++++-----------
 pandas/io/parsers/readers.py                  |  3 +-
 pandas/tests/frame/methods/test_to_csv.py     |  3 +-
 .../io/parser/common/test_common_basic.py     | 40 +++++------
 .../tests/io/parser/common/test_iterator.py   |  4 +-
 pandas/tests/io/parser/conftest.py            | 11 +++
 pandas/tests/io/test_compression.py           |  6 +-
 pandas/tests/series/methods/test_to_csv.py    | 15 ++--
 8 files changed, 79 insertions(+), 71 deletions(-)

diff --git a/pandas/io/excel/_base.py b/pandas/io/excel/_base.py
index b1a2a3824efc9..8284229aa158d 100644
--- a/pandas/io/excel/_base.py
+++ b/pandas/io/excel/_base.py
@@ -601,49 +601,41 @@ def parse(
                                 data[row][col] = last
                             else:
                                 last = data[row][col]
-            future_warnings = []
+
             # GH 12292 : error when read one empty column from excel file
             try:
-                # Gotta catch deprecation warnings to raise at correct stacklevel :(
-                with warnings.catch_warnings(record=True) as w:
-                    parser = TextParser(
-                        data,
-                        names=names,
-                        header=header,
-                        index_col=index_col,
-                        has_index_names=has_index_names,
-                        squeeze=squeeze,
-                        dtype=dtype,
-                        true_values=true_values,
-                        false_values=false_values,
-                        skiprows=skiprows,
-                        nrows=nrows,
-                        na_values=na_values,
-                        skip_blank_lines=False,  # GH 39808
-                        parse_dates=parse_dates,
-                        date_parser=date_parser,
-                        thousands=thousands,
-                        comment=comment,
-                        skipfooter=skipfooter,
-                        usecols=usecols,
-                        mangle_dupe_cols=mangle_dupe_cols,
-                        **kwds,
-                    )
+                parser = TextParser(
+                    data,
+                    names=names,
+                    header=header,
+                    index_col=index_col,
+                    has_index_names=has_index_names,
+                    squeeze=squeeze,
+                    dtype=dtype,
+                    true_values=true_values,
+                    false_values=false_values,
+                    skiprows=skiprows,
+                    nrows=nrows,
+                    na_values=na_values,
+                    skip_blank_lines=False,  # GH 39808
+                    parse_dates=parse_dates,
+                    date_parser=date_parser,
+                    thousands=thousands,
+                    comment=comment,
+                    skipfooter=skipfooter,
+                    usecols=usecols,
+                    mangle_dupe_cols=mangle_dupe_cols,
+                    **kwds,
+                )
 
-                    output[asheetname] = parser.read(nrows=nrows)
+                output[asheetname] = parser.read(nrows=nrows)
 
-                    if not squeeze or isinstance(output[asheetname], DataFrame):
-                        if header_names:
-                            output[asheetname].columns = output[
-                                asheetname
-                            ].columns.set_names(header_names)
+                if not squeeze or isinstance(output[asheetname], DataFrame):
+                    if header_names:
+                        output[asheetname].columns = output[
+                            asheetname
+                        ].columns.set_names(header_names)
 
-                    # Record warning messages, can't raise here since it would be
-                    # suppressed again
-                    for warning in w:
-                        future_warnings.append(str(warning.message))
-                for warning in future_warnings:
-                    warnings.warn(warning, FutureWarning, stacklevel=5)
             except EmptyDataError:
                 # No Data, return an empty DataFrame
                 output[asheetname] = DataFrame()
diff --git a/pandas/io/parsers/readers.py b/pandas/io/parsers/readers.py
index 0782da49dc939..ec58e11aa71db 100644
--- a/pandas/io/parsers/readers.py
+++ b/pandas/io/parsers/readers.py
@@ -28,6 +28,7 @@
     Appender,
     deprecate_nonkeyword_arguments,
 )
+from pandas.util._exceptions import find_stack_level
 from pandas.util._validators import validate_bool_kwarg
 
 from pandas.core.dtypes.common import (
@@ -1059,7 +1060,7 @@ def _clean_options(self, options, engine):
                     f"The {arg} argument has been deprecated and will be "
                     "removed in a future version.\n\n"
                 )
-                warnings.warn(msg, FutureWarning, stacklevel=7)
+                warnings.warn(msg, FutureWarning, stacklevel=find_stack_level())
             else:
                 result[arg] = parser_default
 
diff --git a/pandas/tests/frame/methods/test_to_csv.py b/pandas/tests/frame/methods/test_to_csv.py
index 5156d0371e9b7..be84eb9c85663 100644
--- a/pandas/tests/frame/methods/test_to_csv.py
+++ b/pandas/tests/frame/methods/test_to_csv.py
@@ -1039,8 +1039,7 @@ def test_to_csv_compression(self, df, encoding, compression):
                 compression=compression,
                 encoding=encoding,
                 index_col=0,
-                squeeze=True,
-            )
+            ).squeeze("columns")
             tm.assert_frame_equal(df, result)
 
             # explicitly make sure file is compressed
diff --git a/pandas/tests/io/parser/common/test_common_basic.py b/pandas/tests/io/parser/common/test_common_basic.py
index 8d517f04f3219..3e8e70e7f94a9 100644
--- a/pandas/tests/io/parser/common/test_common_basic.py
+++ b/pandas/tests/io/parser/common/test_common_basic.py
@@ -139,24 +139,25 @@ def test_squeeze(all_parsers, squeeze):
     index = Index(["a", "b", "c"], name=0)
     expected = Series([1, 2, 3], name=1, index=index)
 
-    with tm.assert_produces_warning(
+    result = parser.read_csv_check_warnings(
         FutureWarning,
-        match="The squeeze argument has been deprecated "
+        "The squeeze argument has been deprecated "
         "and will be removed in a future version.\n\n",
-    ):
-        result = parser.read_csv(
-            StringIO(data), index_col=0, header=None, squeeze=squeeze
-        )
-        if not squeeze:
-            expected = DataFrame(expected)
-            tm.assert_frame_equal(result, expected)
-        else:
-            tm.assert_series_equal(result, expected)
+        StringIO(data),
+        index_col=0,
+        header=None,
+        squeeze=squeeze,
+    )
+    if not squeeze:
+        expected = DataFrame(expected)
+        tm.assert_frame_equal(result, expected)
+    else:
+        tm.assert_series_equal(result, expected)
 
-            # see gh-8217
-            #
-            # Series should not be a view.
-            assert not result._is_view
+        # see gh-8217
+        #
+        # Series should not be a view.
+        assert not result._is_view
 
 
 @xfail_pyarrow
@@ -859,12 +860,13 @@ def test_deprecated_bad_lines_warns(all_parsers, csv1, on_bad_lines):
     # GH 15122
     parser = all_parsers
     kwds = {f"{on_bad_lines}_bad_lines": False}
-    with tm.assert_produces_warning(
+    parser.read_csv_check_warnings(
         FutureWarning,
-        match=f"The {on_bad_lines}_bad_lines argument has been deprecated "
+        f"The {on_bad_lines}_bad_lines argument has been deprecated "
         "and will be removed in a future version.\n\n",
-    ):
-        parser.read_csv(csv1, **kwds)
+        csv1,
+        **kwds,
+    )
 
 
 def test_malformed_second_line(all_parsers):
diff --git a/pandas/tests/io/parser/common/test_iterator.py b/pandas/tests/io/parser/common/test_iterator.py
index 06ce0687e513a..3ffa10b73848b 100644
--- a/pandas/tests/io/parser/common/test_iterator.py
+++ b/pandas/tests/io/parser/common/test_iterator.py
@@ -94,7 +94,7 @@ def test_iterator_skipfooter_errors(all_parsers, kwargs):
 
 def test_iteration_open_handle(all_parsers):
     parser = all_parsers
-    kwargs = {"squeeze": True, "header": None}
+    kwargs = {"header": None}
 
     with tm.ensure_clean() as path:
         with open(path, "w") as f:
@@ -105,6 +105,6 @@ def test_iteration_open_handle(all_parsers):
                 if "CCC" in line:
                     break
 
-            result = parser.read_csv(f, **kwargs)
+            result = parser.read_csv(f, **kwargs).squeeze("columns")
             expected = Series(["DDD", "EEE", "FFF", "GGG"], name=0)
             tm.assert_series_equal(result, expected)
diff --git a/pandas/tests/io/parser/conftest.py b/pandas/tests/io/parser/conftest.py
index 372034e552b25..d5fb467e5b01d 100644
--- a/pandas/tests/io/parser/conftest.py
+++ b/pandas/tests/io/parser/conftest.py
@@ -10,6 +10,7 @@
     read_csv,
     read_table,
 )
+import pandas._testing as tm
 
 
 class BaseParser:
@@ -27,6 +28,16 @@ def read_csv(self, *args, **kwargs):
         kwargs = self.update_kwargs(kwargs)
         return read_csv(*args, **kwargs)
 
+    def read_csv_check_warnings(
+        self, warn_type: Warning, warn_msg: str, *args, **kwargs
+    ):
+        # We need to check the stacklevel here instead of in the tests
+        # since this is where read_csv is called and where the warning
+        # should point to.
+        kwargs = self.update_kwargs(kwargs)
+        with tm.assert_produces_warning(warn_type, match=warn_msg):
+            return read_csv(*args, **kwargs)
+
     def read_table(self, *args, **kwargs):
         kwargs = self.update_kwargs(kwargs)
         return read_table(*args, **kwargs)
diff --git a/pandas/tests/io/test_compression.py b/pandas/tests/io/test_compression.py
index 6c90830639061..f6f972fcf4f6a 100644
--- a/pandas/tests/io/test_compression.py
+++ b/pandas/tests/io/test_compression.py
@@ -95,7 +95,11 @@ def test_series_compression_defaults_to_infer(
     extension = icom._compression_to_extension[compression_only]
     with tm.ensure_clean("compressed" + extension) as path:
         getattr(input, write_method)(path, **write_kwargs)
-        output = read_method(path, compression=compression_only, **read_kwargs)
+        if "squeeze" in read_kwargs:
+            del read_kwargs["squeeze"]
+            output = read_method(
+                path, compression=compression_only, **read_kwargs
+            ).squeeze("columns")
     tm.assert_series_equal(output, input, check_names=False)
 
 
diff --git a/pandas/tests/series/methods/test_to_csv.py b/pandas/tests/series/methods/test_to_csv.py
index 9684546112078..28519fc9b529f 100644
--- a/pandas/tests/series/methods/test_to_csv.py
+++ b/pandas/tests/series/methods/test_to_csv.py
@@ -13,11 +13,11 @@
 
 class TestSeriesToCSV:
     def read_csv(self, path, **kwargs):
-        params = {"squeeze": True, "index_col": 0, "header": None, "parse_dates": True}
+        params = {"index_col": 0, "header": None, "parse_dates": True}
         params.update(**kwargs)
 
         header = params.get("header")
-        out = pd.read_csv(path, **params)
+        out = pd.read_csv(path, **params).squeeze("columns")
 
         if header is None:
             out.name = out.index.name = None
@@ -138,8 +138,7 @@ def test_to_csv_compression(self, s, encoding, compression):
                 compression=compression,
                 encoding=encoding,
                 index_col=0,
-                squeeze=True,
-            )
+            ).squeeze("columns")
             tm.assert_series_equal(s, result)
 
             # test the round trip using file handle - to_csv -> read_csv
@@ -153,8 +152,7 @@ def test_to_csv_compression(self, s, encoding, compression):
                 compression=compression,
                 encoding=encoding,
                 index_col=0,
-                squeeze=True,
-            )
+            ).squeeze("columns")
             tm.assert_series_equal(s, result)
 
             # explicitly ensure file was compressed
@@ -164,7 +162,8 @@ def test_to_csv_compression(self, s, encoding, compression):
 
             with tm.decompress_file(filename, compression) as fh:
                 tm.assert_series_equal(
-                    s, pd.read_csv(fh, index_col=0, squeeze=True, encoding=encoding)
+                    s,
+                    pd.read_csv(fh, index_col=0, encoding=encoding).squeeze("columns"),
                 )
 
     def test_to_csv_interval_index(self):
@@ -173,7 +172,7 @@ def test_to_csv_interval_index(self):
 
         with tm.ensure_clean("__tmp_to_csv_interval_index__.csv") as path:
             s.to_csv(path, header=False)
-            result = self.read_csv(path, index_col=0, squeeze=True)
+            result = self.read_csv(path, index_col=0)
 
             # can't roundtrip intervalindex via read_csv so check string repr (GH 23595)
             expected = s.copy()

From a74ade6ba9ce822023353ecd528d043f80ab5edd Mon Sep 17 00:00:00 2001
From: Thomas Li <thomasli1234567890@gmail.com>
Date: Wed, 8 Sep 2021 16:54:47 -0700
Subject: [PATCH 4/9] more fixes

---
 pandas/tests/io/test_compression.py | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/io/test_compression.py b/pandas/tests/io/test_compression.py
index f6f972fcf4f6a..3c278cb48e20f 100644
--- a/pandas/tests/io/test_compression.py
+++ b/pandas/tests/io/test_compression.py
@@ -96,10 +96,13 @@ def test_series_compression_defaults_to_infer(
     with tm.ensure_clean("compressed" + extension) as path:
         getattr(input, write_method)(path, **write_kwargs)
         if "squeeze" in read_kwargs:
-            del read_kwargs["squeeze"]
-            output = read_method(
-                path, compression=compression_only, **read_kwargs
-            ).squeeze("columns")
+            kwargs = read_kwargs.copy()
+            del kwargs["squeeze"]
+            output = read_method(path, compression=compression_only, **kwargs).squeeze(
+                "columns"
+            )
+        else:
+            output = read_method(path, compression=compression_only, **read_kwargs)
     tm.assert_series_equal(output, input, check_names=False)
 
 

From bbdeb912c646977bf2db75e33c9696932bf234b0 Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Wed, 8 Sep 2021 17:37:53 -0700
Subject: [PATCH 5/9] Update io.rst

---
 doc/source/user_guide/io.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/user_guide/io.rst b/doc/source/user_guide/io.rst
index ab9dec2365971..c69f17512a8ea 100644
--- a/doc/source/user_guide/io.rst
+++ b/doc/source/user_guide/io.rst
@@ -1221,6 +1221,7 @@ as a ``Series``:
        fh.write(data)
 
 .. ipython:: python
+   :okwarning:
 
    print(open("tmp.csv").read())
 

From 71ccbb1bad6fc7f7e0d8db56601c3124c76497eb Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Wed, 8 Sep 2021 19:29:25 -0700
Subject: [PATCH 6/9] Update conftest.py

---
 pandas/tests/io/parser/conftest.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/io/parser/conftest.py b/pandas/tests/io/parser/conftest.py
index d5fb467e5b01d..efef06ef28574 100644
--- a/pandas/tests/io/parser/conftest.py
+++ b/pandas/tests/io/parser/conftest.py
@@ -29,7 +29,7 @@ def read_csv(self, *args, **kwargs):
         return read_csv(*args, **kwargs)
 
     def read_csv_check_warnings(
-        self, warn_type: Warning, warn_msg: str, *args, **kwargs
+        self, warn_type: type[Warning], warn_msg: str, *args, **kwargs
     ):
         # We need to check the stacklevel here instead of in the tests
         # since this is where read_csv is called and where the warning

From da725dec78ee47a8ffc3b702674b8a27ad559ef4 Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Wed, 8 Sep 2021 20:52:25 -0700
Subject: [PATCH 7/9] Update _base.py

---
 pandas/io/excel/_base.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pandas/io/excel/_base.py b/pandas/io/excel/_base.py
index 8284229aa158d..51df814ff0ece 100644
--- a/pandas/io/excel/_base.py
+++ b/pandas/io/excel/_base.py
@@ -121,9 +121,10 @@
     Returns a subset of the columns according to behavior above.
 squeeze : bool, default False
     If the parsed data only contains one column then return a Series.
+
     .. deprecated:: 1.4.0
-        Append ``.squeeze("columns")`` to the call to ``read_excel`` to squeeze
-        the data.
+       Append ``.squeeze("columns")`` to the call to ``read_excel`` to squeeze
+       the data.
 dtype : Type name or dict of column -> type, default None
     Data type for data or columns. E.g. {'a': np.float64, 'b': np.int32}
     Use `object` to preserve data as stored in Excel and not interpret dtype.

From 5a7d25a1779bab05ef50f37be44ccd83124511a2 Mon Sep 17 00:00:00 2001
From: Thomas Li <thomasli1234567890@gmail.com>
Date: Thu, 9 Sep 2021 18:11:55 -0700
Subject: [PATCH 8/9] Changes from code review

---
 pandas/io/parsers/readers.py                   | 4 ++--
 pandas/tests/io/parser/common/test_iterator.py | 7 +++----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/pandas/io/parsers/readers.py b/pandas/io/parsers/readers.py
index ec58e11aa71db..439ae3f32c972 100644
--- a/pandas/io/parsers/readers.py
+++ b/pandas/io/parsers/readers.py
@@ -1111,8 +1111,8 @@ def _clean_options(self, options, engine):
         result["na_fvalues"] = na_fvalues
         result["skiprows"] = skiprows
         # Default for squeeze is none since we need to check
-        # if user sets it, we set to False since behavior is
-        # equivlent
+        # if user sets it. We then set to False to preserve
+        # previous behavior.
         result["squeeze"] = False if options["squeeze"] is None else options["squeeze"]
 
         return result, engine
diff --git a/pandas/tests/io/parser/common/test_iterator.py b/pandas/tests/io/parser/common/test_iterator.py
index 3ffa10b73848b..5966a2fd6e095 100644
--- a/pandas/tests/io/parser/common/test_iterator.py
+++ b/pandas/tests/io/parser/common/test_iterator.py
@@ -8,7 +8,6 @@
 
 from pandas import (
     DataFrame,
-    Series,
     concat,
 )
 import pandas._testing as tm
@@ -105,6 +104,6 @@ def test_iteration_open_handle(all_parsers):
                 if "CCC" in line:
                     break
 
-            result = parser.read_csv(f, **kwargs).squeeze("columns")
-            expected = Series(["DDD", "EEE", "FFF", "GGG"], name=0)
-            tm.assert_series_equal(result, expected)
+            result = parser.read_csv(f, **kwargs)
+            expected = DataFrame({0: ["DDD", "EEE", "FFF", "GGG"]})
+            tm.assert_frame_equal(result, expected)

From 71d4f7a27259013387bad5fe741eaf8fbccf9fb6 Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Thu, 9 Sep 2021 20:06:39 -0700
Subject: [PATCH 9/9] Update pandas/io/parsers/readers.py

Co-authored-by: gfyoung <gfyoung17+GitHub@gmail.com>
---
 pandas/io/parsers/readers.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/io/parsers/readers.py b/pandas/io/parsers/readers.py
index 439ae3f32c972..afbe37b2ef44c 100644
--- a/pandas/io/parsers/readers.py
+++ b/pandas/io/parsers/readers.py
@@ -134,7 +134,7 @@
     If the parsed data only contains one column then return a Series.
 
     .. deprecated:: 1.4.0
-        Append ``.squeeze("columns")`` to the call to ``read_csv`` to squeeze
+        Append ``.squeeze("columns")`` to the call to ``{func_name}`` to squeeze
         the data.
 prefix : str, optional
     Prefix to add to column numbers when no header, e.g. 'X' for X0, X1, ...