ENH: Add index option to_markdown()

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`)
 -
 
 .. ---------------------------------------------------------------------------

pandas/core/frame.py

@@ -2091,10 +2091,18 @@ 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:
+            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)
         tabulate = import_optional_dependency("tabulate")
         result = tabulate.tabulate(self, **kwargs)
         if buf is None:

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`.
 

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)
 
     # ----------------------------------------------------------------------
 

pandas/tests/io/formats/test_to_markdown.py

@@ -53,3 +53,31 @@ 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):
+    # GH 32667
+    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.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)]:
+            assert result == (
+                "|    |   0 |\n|---:|----:|\n"
+                "|  0 |   1 |\n|  1 |   2 |\n|  2 |   3 |"
+            )
+        else:
+            assert result == "|   0 |\n|----:|\n|   1 |\n|   2 |\n|   3 |"