ENH: Implement xlabel and ylabel options in Series.plot and DataFrame.plot

doc/source/user_guide/visualization.rst

@@ -1108,6 +1108,34 @@ shown by default.
 
    plt.close('all')
 
+
+Controlling the labels
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 1.1.0
+
+You may set the ``xlabel`` and ``ylabel`` arguments to give the plot custom labels
+for x and y axis. By default, pandas will pick up index name as xlabel, while leaving
+it empty for ylabel.
+
+.. ipython:: python
+   :suppress:
+
+   plt.figure()
+
+.. ipython:: python
+
+   df.plot()
+
+   @savefig plot_xlabel_ylabel.png
+   df.plot(xlabel="new x", ylabel="new y")
+
+.. ipython:: python
+   :suppress:
+
+   plt.close('all')
+
+
 Scales
 ~~~~~~
 

doc/source/whatsnew/v1.1.0.rst

@@ -303,6 +303,7 @@ Other enhancements
   :class:`~pandas.io.stata.StataWriter`, :class:`~pandas.io.stata.StataWriter117`,
   and :class:`~pandas.io.stata.StataWriterUTF8` (:issue:`26599`).
 - :meth:`HDFStore.put` now accepts `track_times` parameter. Parameter is passed to ``create_table`` method of ``PyTables`` (:issue:`32682`).
+- :meth:`Series.plot` and :meth:`DataFrame.plot` now accepts `xlabel` and `ylabel` parameters to present labels on x and y axis (:issue:`9093`).
 - Make :class:`pandas.core.window.Rolling` and :class:`pandas.core.window.Expanding` iterable（:issue:`11704`)
 - Make ``option_context`` a :class:`contextlib.ContextDecorator`, which allows it to be used as a decorator over an entire function (:issue:`34253`).
 - :meth:`DataFrame.to_csv` and :meth:`Series.to_csv` now accept an ``errors`` argument (:issue:`22610`)

pandas/plotting/_core.py

@@ -673,6 +673,16 @@ class PlotAccessor(PandasObject):
         Set the x limits of the current axes.
     ylim : 2-tuple/list
         Set the y limits of the current axes.
+    xlabel : label, optional
+        Name to use for the xlabel on x-axis. Default uses index name as xlabel.
+
+        .. versionadded:: 1.1.0
+
+    ylabel : label, optional
+        Name to use for the ylabel on y-axis. Default will show no ylabel.
+
+        .. versionadded:: 1.1.0
+
     rot : int, default None
         Rotation for ticks (xticks for vertical, yticks for horizontal
         plots).
@@ -779,6 +789,8 @@ def _get_call_args(backend_name, data, args, kwargs):
                 ("xerr", None),
                 ("label", None),
                 ("secondary_y", False),
+                ("xlabel", None),
+                ("ylabel", None),
             ]
         elif isinstance(data, ABCDataFrame):
             arg_def = [
@@ -811,6 +823,8 @@ def _get_call_args(backend_name, data, args, kwargs):
                 ("xerr", None),
                 ("secondary_y", False),
                 ("sort_columns", False),
+                ("xlabel", None),
+                ("ylabel", None),
             ]
         else:
             raise TypeError(

pandas/plotting/_matplotlib/core.py

@@ -1,9 +1,11 @@
 import re
-from typing import Optional
+from typing import List, Optional
 import warnings
 
+from matplotlib.artist import Artist
 import numpy as np
 
+from pandas._typing import Label
 from pandas.errors import AbstractMethodError
 from pandas.util._decorators import cache_readonly
 
@@ -97,6 +99,8 @@ def __init__(
         ylim=None,
         xticks=None,
         yticks=None,
+        xlabel: Optional[Label] = None,
+        ylabel: Optional[Label] = None,
         sort_columns=False,
         fontsize=None,
         secondary_y=False,
@@ -138,6 +142,8 @@ def __init__(
         self.ylim = ylim
         self.title = title
         self.use_index = use_index
+        self.xlabel = xlabel
+        self.ylabel = ylabel
 
         self.fontsize = fontsize
 
@@ -155,8 +161,8 @@ def __init__(
 
         self.grid = grid
         self.legend = legend
-        self.legend_handles = []
-        self.legend_labels = []
+        self.legend_handles: List[Artist] = []
+        self.legend_labels: List[Label] = []
 
         for attr in self._pop_attributes:
             value = kwds.pop(attr, self._attr_defaults.get(attr, None))
@@ -482,6 +488,11 @@ def _adorn_subplots(self):
             if self.xlim is not None:
                 ax.set_xlim(self.xlim)
 
+            # GH9093, currently Pandas does not show ylabel, so if users provide
+            # ylabel will set it as ylabel in the plot.
+            if self.ylabel is not None:
+                ax.set_ylabel(pprint_thing(self.ylabel))
+
             ax.grid(self.grid)
 
         if self.title:
@@ -668,6 +679,10 @@ def _get_index_name(self):
             if name is not None:
                 name = pprint_thing(name)
 
+        # GH 9093, override the default xlabel if xlabel is provided.
+        if self.xlabel is not None:
+            name = pprint_thing(self.xlabel)
+
         return name
 
     @classmethod

pandas/tests/plotting/test_frame.py

@@ -3363,6 +3363,62 @@ def test_colors_of_columns_with_same_name(self):
         for legend, line in zip(result.get_legend().legendHandles, result.lines):
             assert legend.get_color() == line.get_color()
 
+    @pytest.mark.parametrize(
+        "index_name, old_label, new_label",
+        [
+            (None, "", "new"),
+            ("old", "old", "new"),
+            (None, "", ""),
+            (None, "", 1),
+            (None, "", [1, 2]),
+        ],
+    )
+    @pytest.mark.parametrize("kind", ["line", "area", "bar"])
+    def test_xlabel_ylabel_dataframe_single_plot(
+        self, kind, index_name, old_label, new_label
+    ):
+        # GH 9093
+        df = pd.DataFrame([[1, 2], [2, 5]], columns=["Type A", "Type B"])
+        df.index.name = index_name
+
+        # default is the ylabel is not shown and xlabel is index name
+        ax = df.plot(kind=kind)
+        assert ax.get_xlabel() == old_label
+        assert ax.get_ylabel() == ""
+
+        # old xlabel will be overriden and assigned ylabel will be used as ylabel
+        ax = df.plot(kind=kind, ylabel=new_label, xlabel=new_label)
+        assert ax.get_ylabel() == str(new_label)
+        assert ax.get_xlabel() == str(new_label)
+
+    @pytest.mark.parametrize(
+        "index_name, old_label, new_label",
+        [
+            (None, "", "new"),
+            ("old", "old", "new"),
+            (None, "", ""),
+            (None, "", 1),
+            (None, "", [1, 2]),
+        ],
+    )
+    @pytest.mark.parametrize("kind", ["line", "area", "bar"])
+    def test_xlabel_ylabel_dataframe_subplots(
+        self, kind, index_name, old_label, new_label
+    ):
+        # GH 9093
+        df = pd.DataFrame([[1, 2], [2, 5]], columns=["Type A", "Type B"])
+        df.index.name = index_name
+
+        # default is the ylabel is not shown and xlabel is index name
+        axes = df.plot(kind=kind, subplots=True)
+        assert all(ax.get_ylabel() == "" for ax in axes)
+        assert all(ax.get_xlabel() == old_label for ax in axes)
+
+        # old xlabel will be overriden and assigned ylabel will be used as ylabel
+        axes = df.plot(kind=kind, ylabel=new_label, xlabel=new_label, subplots=True)
+        assert all(ax.get_ylabel() == str(new_label) for ax in axes)
+        assert all(ax.get_xlabel() == str(new_label) for ax in axes)
+
 
 def _generate_4_axes_via_gridspec():
     import matplotlib.pyplot as plt

pandas/tests/plotting/test_misc.py

@@ -54,7 +54,7 @@ def test_get_accessor_args():
     assert x is None
     assert y is None
     assert kind == "line"
-    assert len(kwargs) == 22
+    assert len(kwargs) == 24
 
 
 @td.skip_if_no_mpl

pandas/tests/plotting/test_series.py

@@ -934,3 +934,23 @@ def test_style_single_ok(self):
         s = pd.Series([1, 2])
         ax = s.plot(style="s", color="C3")
         assert ax.lines[0].get_color() == ["C3"]
+
+    @pytest.mark.parametrize(
+        "index_name, old_label, new_label",
+        [(None, "", "new"), ("old", "old", "new"), (None, "", "")],
+    )
+    @pytest.mark.parametrize("kind", ["line", "area", "bar"])
+    def test_xlabel_ylabel_series(self, kind, index_name, old_label, new_label):
+        # GH 9093
+        ser = pd.Series([1, 2, 3, 4])
+        ser.index.name = index_name
+
+        # default is the ylabel is not shown and xlabel is index name
+        ax = ser.plot(kind=kind)
+        assert ax.get_ylabel() == ""
+        assert ax.get_xlabel() == old_label
+
+        # old xlabel will be overriden and assigned ylabel will be used as ylabel
+        ax = ser.plot(kind=kind, ylabel=new_label, xlabel=new_label)
+        assert ax.get_ylabel() == new_label
+        assert ax.get_xlabel() == new_label