From 5bfdc2154c0fa863c739b824454237c8004273b9 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Sat, 28 Mar 2020 10:25:27 +0700
Subject: [PATCH 01/18] add index kw and tests

---
 pandas/core/frame.py                        | 15 +++++++++++-
 pandas/tests/io/formats/test_to_markdown.py | 27 +++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 1e9f8995b6bed..38211f1ab3f0b 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2091,10 +2091,23 @@ def to_feather(self, path) -> None:
     @Substitution(klass="DataFrame")
     @Appender(_shared_docs["to_markdown"])
     def to_markdown(
-        self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
+        self,
+        buf: Optional[IO[str]] = None,
+        mode: Optional[str] = None,
+        index: Optional[bool] = None,
+        **kwargs,
     ) -> Optional[str]:
+        if index is not None and "showindex" in kwargs:
+            warnings.warn(
+                "Index and showindex are aliases. Setting them both "
+                "causes undefined behaviour and could be "
+                "subjected to changes in the future.",
+                UserWarning,
+                stacklevel=3,
+            )
         kwargs.setdefault("headers", "keys")
         kwargs.setdefault("tablefmt", "pipe")
+        kwargs.setdefault("showindex", True if index is None else index)
         tabulate = import_optional_dependency("tabulate")
         result = tabulate.tabulate(self, **kwargs)
         if buf is None:
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 8893e4294353f..c8c136b721925 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -53,3 +53,30 @@ def test_no_buf(capsys):
     assert (
         result == "|    |   0 |\n|---:|----:|\n|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
     )
+
+
+@pytest.mark.parametrize("index", [True, False, None])
+@pytest.mark.parametrize("showindex", [True, False, None])
+def test_index(index, showindex):
+    kwargs = {}
+    if index is not None:
+        kwargs["index"] = index
+    if showindex is not None:
+        kwargs["showindex"] = showindex
+
+    df = pd.DataFrame([1, 2, 3])
+
+    if "index" in kwargs and "showindex" in kwargs:
+        msg = "Index and showindex are aliases"
+        with pytest.warns(UserWarning, match=msg):
+            df.to_markdown(**kwargs)
+    else:
+        # only one or none is set
+        result = df.to_markdown(**kwargs)
+        if (index, showindex) in [(True, None), (None, True), (None, None)]:
+            assert result == (
+                "|    |   0 |\n|---:|----:|\n"
+                "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
+            )
+        else:
+            assert result == "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"

From d74be05a4519a8d38aa25362a17bf2f57f8abbba Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Sat, 28 Mar 2020 10:34:50 +0700
Subject: [PATCH 02/18] add for series, edit docs

---
 pandas/core/generic.py | 2 ++
 pandas/core/series.py  | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 5348040808e63..807149765bc92 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -1903,6 +1903,8 @@ def _repr_data_resource_(self):
         Buffer to write to. If None, the output is returned as a string.
     mode : str, optional
         Mode in which file is opened.
+    index : bool, optional
+        Whether to print index (row) labels.
     **kwargs
         These parameters will be passed to `tabulate`.
 
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 39e1178a3a5c3..6bc049e8a5aee 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1457,9 +1457,13 @@ def to_string(
     @Substitution(klass="Series")
     @Appender(generic._shared_docs["to_markdown"])
     def to_markdown(
-        self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
+        self,
+        buf: Optional[IO[str]] = None,
+        mode: Optional[str] = None,
+        index: Optional[bool] = None,
+        **kwargs,
     ) -> Optional[str]:
-        return self.to_frame().to_markdown(buf, mode, **kwargs)
+        return self.to_frame().to_markdown(buf, mode, index, **kwargs)
 
     # ----------------------------------------------------------------------
 

From decac71c3e05ce55ef366145c370e34f216b4c63 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Mon, 30 Mar 2020 11:33:31 +0700
Subject: [PATCH 03/18] add comment and doc

---
 doc/source/whatsnew/v1.1.0.rst              | 1 +
 pandas/tests/io/formats/test_to_markdown.py | 1 +
 2 files changed, 2 insertions(+)

diff --git a/doc/source/whatsnew/v1.1.0.rst b/doc/source/whatsnew/v1.1.0.rst
index 20415bba99476..79cdd88249142 100644
--- a/doc/source/whatsnew/v1.1.0.rst
+++ b/doc/source/whatsnew/v1.1.0.rst
@@ -71,6 +71,7 @@ Other enhancements
 - Positional slicing on a :class:`IntervalIndex` now supports slices with ``step > 1`` (:issue:`31658`)
 - :class:`Series.str` now has a `fullmatch` method that matches a regular expression against the entire string in each row of the series, similar to `re.fullmatch` (:issue:`32806`).
 - :meth:`DataFrame.sample` will now also allow array-like and BitGenerator objects to be passed to ``random_state`` as seeds (:issue:`32503`)
+- :meth:`DataFrame.to_markdown` will now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
 -
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index c8c136b721925..4cfd8b8bdc65f 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -58,6 +58,7 @@ def test_no_buf(capsys):
 @pytest.mark.parametrize("index", [True, False, None])
 @pytest.mark.parametrize("showindex", [True, False, None])
 def test_index(index, showindex):
+    # GH 32667
     kwargs = {}
     if index is not None:
         kwargs["index"] = index

From 12b96a2b00ce06b02844ebc74a33b6e65e080c69 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Mon, 30 Mar 2020 14:15:21 +0700
Subject: [PATCH 04/18] change wanings to error

---
 pandas/core/frame.py                        | 9 ++-------
 pandas/tests/io/formats/test_to_markdown.py | 2 +-
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 38211f1ab3f0b..f3c27345d0ee6 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2098,13 +2098,8 @@ def to_markdown(
         **kwargs,
     ) -> Optional[str]:
         if index is not None and "showindex" in kwargs:
-            warnings.warn(
-                "Index and showindex are aliases. Setting them both "
-                "causes undefined behaviour and could be "
-                "subjected to changes in the future.",
-                UserWarning,
-                stacklevel=3,
-            )
+            raise ValueError("Index and showindex are aliases, please choose one")
+
         kwargs.setdefault("headers", "keys")
         kwargs.setdefault("tablefmt", "pipe")
         kwargs.setdefault("showindex", True if index is None else index)
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 4cfd8b8bdc65f..709a6e4058dc5 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -69,7 +69,7 @@ def test_index(index, showindex):
 
     if "index" in kwargs and "showindex" in kwargs:
         msg = "Index and showindex are aliases"
-        with pytest.warns(UserWarning, match=msg):
+        with pytest.raises(ValueError, match=msg):
             df.to_markdown(**kwargs)
     else:
         # only one or none is set

From ff0b9700ea1025386d49874200ac9845477ff3fb Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Mon, 6 Apr 2020 12:34:03 +0700
Subject: [PATCH 05/18] completely remove showindex kw

---
 pandas/core/frame.py                        |  9 ++++++---
 pandas/core/generic.py                      |  5 ++++-
 pandas/core/series.py                       |  2 +-
 pandas/tests/io/formats/test_to_markdown.py | 11 +++++++----
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index f3c27345d0ee6..5f6a92e186dda 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2094,11 +2094,14 @@ def to_markdown(
         self,
         buf: Optional[IO[str]] = None,
         mode: Optional[str] = None,
-        index: Optional[bool] = None,
+        index: Optional[bool] = True,
         **kwargs,
     ) -> Optional[str]:
-        if index is not None and "showindex" in kwargs:
-            raise ValueError("Index and showindex are aliases, please choose one")
+        if "showindex" in kwargs:
+            raise ValueError(
+                "'showindex' is not a valid keyword argument, "
+                "please use 'index' to control showing the index"
+            )
 
         kwargs.setdefault("headers", "keys")
         kwargs.setdefault("tablefmt", "pipe")
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 807149765bc92..99f3d59561f8b 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -1903,8 +1903,11 @@ def _repr_data_resource_(self):
         Buffer to write to. If None, the output is returned as a string.
     mode : str, optional
         Mode in which file is opened.
-    index : bool, optional
+    index : bool, default True
         Whether to print index (row) labels.
+
+        .. versionadded:: 1.1
+
     **kwargs
         These parameters will be passed to `tabulate`.
 
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 6bc049e8a5aee..059d41db7801f 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1460,7 +1460,7 @@ def to_markdown(
         self,
         buf: Optional[IO[str]] = None,
         mode: Optional[str] = None,
-        index: Optional[bool] = None,
+        index: Optional[bool] = True,
         **kwargs,
     ) -> Optional[str]:
         return self.to_frame().to_markdown(buf, mode, index, **kwargs)
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 709a6e4058dc5..50582498d0acf 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -67,14 +67,17 @@ def test_index(index, showindex):
 
     df = pd.DataFrame([1, 2, 3])
 
-    if "index" in kwargs and "showindex" in kwargs:
-        msg = "Index and showindex are aliases"
+    if "showindex" in kwargs:
+        # force user to use index instead of tabulate's show index
+        msg = (
+            "'showindex' is not a valid keyword argument, "
+            "please use 'index' to control showing the index"
+        )
         with pytest.raises(ValueError, match=msg):
             df.to_markdown(**kwargs)
     else:
-        # only one or none is set
         result = df.to_markdown(**kwargs)
-        if (index, showindex) in [(True, None), (None, True), (None, None)]:
+        if index in [True, None]:
             assert result == (
                 "|    |   0 |\n|---:|----:|\n"
                 "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"

From e519fa340db7cf967c233145e2a06f2ff6336f86 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Quang=20Nguy=E1=BB=85n?=
 <30631476+quangngd@users.noreply.github.com>
Date: Sat, 9 May 2020 08:46:38 +0700
Subject: [PATCH 06/18] Update v1.1.0.rst

---
 doc/source/whatsnew/v1.1.0.rst | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v1.1.0.rst b/doc/source/whatsnew/v1.1.0.rst
index 6f42580e3be30..454659be08c2b 100644
--- a/doc/source/whatsnew/v1.1.0.rst
+++ b/doc/source/whatsnew/v1.1.0.rst
@@ -150,9 +150,8 @@ Other enhancements
   such as ``dict`` and ``list``, mirroring the behavior of :meth:`DataFrame.update` (:issue:`33215`)
 - :meth:`~pandas.core.groupby.GroupBy.transform` and :meth:`~pandas.core.groupby.GroupBy.aggregate` has gained ``engine`` and ``engine_kwargs`` arguments that supports executing functions with ``Numba`` (:issue:`32854`, :issue:`33388`)
 - :meth:`~pandas.core.resample.Resampler.interpolate` now supports SciPy interpolation method :class:`scipy.interpolate.CubicSpline` as method ``cubicspline`` (:issue:`33670`)
-- :meth:`DataFrame.to_markdown` will now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
-- :meth:`DataFrame.to_markdown` will now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
 - :meth:`MultiIndex.union` will now raise `RuntimeWarning` if the object inside are unsortable, pass `sort=False` to suppress this warning (:issue:`33015`)
+- :meth:`DataFrame.to_markdown` will now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
 -
 
 .. ---------------------------------------------------------------------------

From 8cc92c1e95615d1de883967c20172a20d6acfd23 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Quang=20Nguy=E1=BB=85n?=
 <30631476+quangngd@users.noreply.github.com>
Date: Sat, 9 May 2020 08:47:32 +0700
Subject: [PATCH 07/18] Update v1.1.0.rst

---
 doc/source/whatsnew/v1.1.0.rst | 1 -
 1 file changed, 1 deletion(-)

diff --git a/doc/source/whatsnew/v1.1.0.rst b/doc/source/whatsnew/v1.1.0.rst
index 454659be08c2b..9bdf3826d764e 100644
--- a/doc/source/whatsnew/v1.1.0.rst
+++ b/doc/source/whatsnew/v1.1.0.rst
@@ -150,7 +150,6 @@ Other enhancements
   such as ``dict`` and ``list``, mirroring the behavior of :meth:`DataFrame.update` (:issue:`33215`)
 - :meth:`~pandas.core.groupby.GroupBy.transform` and :meth:`~pandas.core.groupby.GroupBy.aggregate` has gained ``engine`` and ``engine_kwargs`` arguments that supports executing functions with ``Numba`` (:issue:`32854`, :issue:`33388`)
 - :meth:`~pandas.core.resample.Resampler.interpolate` now supports SciPy interpolation method :class:`scipy.interpolate.CubicSpline` as method ``cubicspline`` (:issue:`33670`)
-- :meth:`MultiIndex.union` will now raise `RuntimeWarning` if the object inside are unsortable, pass `sort=False` to suppress this warning (:issue:`33015`)
 - :meth:`DataFrame.to_markdown` will now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
 -
 

From 492f72ff47b30a701b532f18701b13c3290d2869 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Thu, 18 Jun 2020 15:15:39 +0700
Subject: [PATCH 08/18] change ValueError to FutureWarning

---
 pandas/core/frame.py                        | 10 +++++++---
 pandas/tests/io/formats/test_to_markdown.py | 19 ++++++++++++-------
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index a7cab266c1d90..05aa67c27568e 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2141,9 +2141,13 @@ def to_markdown(
         **kwargs,
     ) -> Optional[str]:
         if "showindex" in kwargs:
-            raise ValueError(
-                "'showindex' is not a valid keyword argument, "
-                "please use 'index' to control showing the index"
+            index = kwargs["showindex"]
+            del kwargs["showindex"]
+
+            warnings.warn(
+                "'showindex' is deprecated. Only 'index' will be used "
+                "in a future version. Use 'index' to silence this warning.",
+                FutureWarning,
             )
 
         kwargs.setdefault("headers", "keys")
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 50582498d0acf..4ddf8ce51357e 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -68,13 +68,18 @@ def test_index(index, showindex):
     df = pd.DataFrame([1, 2, 3])
 
     if "showindex" in kwargs:
-        # force user to use index instead of tabulate's show index
-        msg = (
-            "'showindex' is not a valid keyword argument, "
-            "please use 'index' to control showing the index"
-        )
-        with pytest.raises(ValueError, match=msg):
-            df.to_markdown(**kwargs)
+        msg = "deprecated"
+        with pytest.warns(FutureWarning, match=msg):
+            result = df.to_markdown(**kwargs)
+
+        # give showindex higher priority if specified
+        if showindex:
+            assert result == (
+                "|    |   0 |\n|---:|----:|\n"
+                "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
+            )
+        else:
+            assert result == "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"
     else:
         result = df.to_markdown(**kwargs)
         if index in [True, None]:

From 5670f670d77750ad56835258f78805ade76f062b Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Wed, 1 Jul 2020 11:24:38 +0700
Subject: [PATCH 09/18] fix warnings

---
 pandas/core/frame.py                        | 1 +
 pandas/tests/io/formats/test_to_markdown.py | 5 +++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 8f363fc25b9dd..41c1b8fea0e54 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2230,6 +2230,7 @@ def to_markdown(
                 "'showindex' is deprecated. Only 'index' will be used "
                 "in a future version. Use 'index' to silence this warning.",
                 FutureWarning,
+                stacklevel=2,
             )
 
         kwargs.setdefault("headers", "keys")
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 4ddf8ce51357e..3a75d1fe82b30 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -3,6 +3,8 @@
 import pytest
 
 import pandas as pd
+import pandas._testing as tm
+
 
 pytest.importorskip("tabulate")
 
@@ -68,8 +70,7 @@ def test_index(index, showindex):
     df = pd.DataFrame([1, 2, 3])
 
     if "showindex" in kwargs:
-        msg = "deprecated"
-        with pytest.warns(FutureWarning, match=msg):
+        with tm.assert_produces_warning(FutureWarning):
             result = df.to_markdown(**kwargs)
 
         # give showindex higher priority if specified

From e80230a16f4151ae5e04fbd9690ddc37ef0fa1e2 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Wed, 1 Jul 2020 11:58:49 +0700
Subject: [PATCH 10/18] fix import

---
 pandas/tests/io/formats/test_to_markdown.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 3a75d1fe82b30..05425c614ded6 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -5,7 +5,6 @@
 import pandas as pd
 import pandas._testing as tm
 
-
 pytest.importorskip("tabulate")
 
 

From 992f923ad630a1b5a26881a87ea0540473afb9ec Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Thu, 2 Jul 2020 15:05:59 +0700
Subject: [PATCH 11/18] refactor test, fix typing and doc

---
 doc/source/whatsnew/v1.1.0.rst              |  2 +-
 pandas/core/frame.py                        |  4 ++--
 pandas/core/series.py                       |  2 +-
 pandas/tests/io/formats/test_to_markdown.py | 18 ++++++++----------
 4 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/doc/source/whatsnew/v1.1.0.rst b/doc/source/whatsnew/v1.1.0.rst
index ac94934f38306..55e9aeec26c61 100644
--- a/doc/source/whatsnew/v1.1.0.rst
+++ b/doc/source/whatsnew/v1.1.0.rst
@@ -328,7 +328,7 @@ Other enhancements
 - :meth:`DataFrame.to_html` and :meth:`DataFrame.to_string`'s ``col_space`` parameter now accepts a list or dict to change only some specific columns' width (:issue:`28917`).
 - :meth:`DataFrame.to_excel` can now also write OpenOffice spreadsheet (.ods) files (:issue:`27222`)
 - :meth:`~Series.explode` now accepts ``ignore_index`` to reset the index, similarly to :meth:`pd.concat` or :meth:`DataFrame.sort_values` (:issue:`34932`).
-- :meth:`DataFrame.to_markdown` will now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
+- :meth:`DataFrame.to_markdown` and :meth:`Series.to_markdown` now accept ``index`` argument as an alias for tabulate's ``showindex`` (:issue:`32667`)
 
 .. ---------------------------------------------------------------------------
 
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 41c1b8fea0e54..c65c476a6ca51 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2219,7 +2219,7 @@ def to_markdown(
         self,
         buf: Optional[IO[str]] = None,
         mode: Optional[str] = None,
-        index: Optional[bool] = True,
+        index: bool = True,
         **kwargs,
     ) -> Optional[str]:
         if "showindex" in kwargs:
@@ -2235,7 +2235,7 @@ def to_markdown(
 
         kwargs.setdefault("headers", "keys")
         kwargs.setdefault("tablefmt", "pipe")
-        kwargs.setdefault("showindex", True if index is None else index)
+        kwargs.setdefault("showindex", index)
         tabulate = import_optional_dependency("tabulate")
         result = tabulate.tabulate(self, **kwargs)
         if buf is None:
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 91c1a49837e0f..24b7e8e486547 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1426,7 +1426,7 @@ def to_markdown(
         self,
         buf: Optional[IO[str]] = None,
         mode: Optional[str] = None,
-        index: Optional[bool] = True,
+        index: bool = True,
         **kwargs,
     ) -> Optional[str]:
         """
diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 05425c614ded6..6e8d16a05fd56 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -67,6 +67,10 @@ def test_index(index, showindex):
         kwargs["showindex"] = showindex
 
     df = pd.DataFrame([1, 2, 3])
+    yes_index_result = (
+        "|    |   0 |\n|---:|----:|\n" "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
+    )
+    no_index_result = "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"
 
     if "showindex" in kwargs:
         with tm.assert_produces_warning(FutureWarning):
@@ -74,18 +78,12 @@ def test_index(index, showindex):
 
         # give showindex higher priority if specified
         if showindex:
-            assert result == (
-                "|    |   0 |\n|---:|----:|\n"
-                "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
-            )
+            assert result == yes_index_result
         else:
-            assert result == "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"
+            assert result == no_index_result
     else:
         result = df.to_markdown(**kwargs)
         if index in [True, None]:
-            assert result == (
-                "|    |   0 |\n|---:|----:|\n"
-                "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
-            )
+            assert result == yes_index_result
         else:
-            assert result == "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"
+            assert result == no_index_result

From 68cf1f7f2595128325e222e98cbd36854a2cedac Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Thu, 2 Jul 2020 15:27:29 +0700
Subject: [PATCH 12/18] fix blacks split line

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

diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index 6e8d16a05fd56..a46b9b467a7d3 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -68,7 +68,7 @@ def test_index(index, showindex):
 
     df = pd.DataFrame([1, 2, 3])
     yes_index_result = (
-        "|    |   0 |\n|---:|----:|\n" "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
+        "|    |   0 |\n|---:|----:|\n|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
     )
     no_index_result = "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"
 

From 9ee640f2b965d90c26da287ddb2a89463ffba563 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Tue, 7 Jul 2020 10:01:25 +0700
Subject: [PATCH 13/18] refactor test

---
 pandas/tests/io/formats/test_to_markdown.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index a46b9b467a7d3..fcf05874595bc 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -72,17 +72,17 @@ def test_index(index, showindex):
     )
     no_index_result = "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"
 
-    if "showindex" in kwargs:
-        with tm.assert_produces_warning(FutureWarning):
-            result = df.to_markdown(**kwargs)
+    warning = FutureWarning if "showindex" in kwargs else None
+    with tm.assert_produces_warning(warning):
+        result = df.to_markdown(**kwargs)
 
+    if "showindex" in kwargs:
         # give showindex higher priority if specified
         if showindex:
             assert result == yes_index_result
         else:
             assert result == no_index_result
     else:
-        result = df.to_markdown(**kwargs)
         if index in [True, None]:
             assert result == yes_index_result
         else:

From 82bb8229243fdec5a8b843722c2a679339804496 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Tue, 7 Jul 2020 15:57:41 +0700
Subject: [PATCH 14/18] refactor test

---
 pandas/tests/io/formats/test_to_markdown.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/io/formats/test_to_markdown.py b/pandas/tests/io/formats/test_to_markdown.py
index fcf05874595bc..5223b313fef4f 100644
--- a/pandas/tests/io/formats/test_to_markdown.py
+++ b/pandas/tests/io/formats/test_to_markdown.py
@@ -79,11 +79,12 @@ def test_index(index, showindex):
     if "showindex" in kwargs:
         # give showindex higher priority if specified
         if showindex:
-            assert result == yes_index_result
+            expected = yes_index_result
         else:
-            assert result == no_index_result
+            expected = no_index_result
     else:
         if index in [True, None]:
-            assert result == yes_index_result
+            expected = yes_index_result
         else:
-            assert result == no_index_result
+            expected = no_index_result
+    assert result == expected

From bc2d998290c3d27c377dd59e02ebcca787988e93 Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Tue, 7 Jul 2020 19:49:40 +0700
Subject: [PATCH 15/18] remove redundant code

---
 pandas/core/frame.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 7660f313ba9e9..ef03d264ff329 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2224,9 +2224,6 @@ def to_markdown(
         **kwargs,
     ) -> Optional[str]:
         if "showindex" in kwargs:
-            index = kwargs["showindex"]
-            del kwargs["showindex"]
-
             warnings.warn(
                 "'showindex' is deprecated. Only 'index' will be used "
                 "in a future version. Use 'index' to silence this warning.",

From c822daf1a3caeb71e007957ce8539a524a9a1d4e Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Wed, 8 Jul 2020 09:53:17 +0700
Subject: [PATCH 16/18] update docstring

---
 pandas/core/series.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index 53d93d24ecd21..43bf270528080 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1436,6 +1436,8 @@ def to_markdown(
             Buffer to write to. If None, the output is returned as a string.
         mode : str, optional
             Mode in which file is opened.
+        index : bool, optional, default True
+            Add index (row) labels
         **kwargs
             These parameters will be passed to `tabulate \
                 <https://pypi.org/project/tabulate>`_.

From 2085ed5f906aa130be97a8e512601633b26cf8fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Quang=20Nguy=E1=BB=85n?=
 <30631476+quangngd@users.noreply.github.com>
Date: Wed, 8 Jul 2020 20:09:00 +0700
Subject: [PATCH 17/18] Update pandas/core/series.py

Co-authored-by: Simon Hawkins <simonjayhawkins@gmail.com>
---
 pandas/core/series.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index 43bf270528080..355807a4b3e9a 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1437,7 +1437,7 @@ def to_markdown(
         mode : str, optional
             Mode in which file is opened.
         index : bool, optional, default True
-            Add index (row) labels
+            Add index (row) labels.
         **kwargs
             These parameters will be passed to `tabulate \
                 <https://pypi.org/project/tabulate>`_.

From 71a9b6bf750bd4a7c9fd05f1e2e4300a490ba49b Mon Sep 17 00:00:00 2001
From: Quang Nguyen <quang.ngduy.ndq@gmail.com>
Date: Wed, 15 Jul 2020 09:57:43 +0700
Subject: [PATCH 18/18] add versionadded

---
 pandas/core/series.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index 43bf270528080..b13702fb8b728 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1438,6 +1438,9 @@ def to_markdown(
             Mode in which file is opened.
         index : bool, optional, default True
             Add index (row) labels
+
+            .. versionadded:: 1.1.0
+
         **kwargs
             These parameters will be passed to `tabulate \
                 <https://pypi.org/project/tabulate>`_.