ENH: Add Styler.pipe() method (#23229)

doc/source/api.rst

@@ -2410,6 +2410,7 @@ Style Application
    Styler.set_properties
    Styler.set_uuid
    Styler.clear
+   Styler.pipe
 
 Builtin Styles
 ~~~~~~~~~~~~~~

doc/source/whatsnew/v0.24.0.txt

@@ -214,6 +214,7 @@ Other Enhancements
 - Compatibility with Matplotlib 3.0 (:issue:`22790`).
 - Added :meth:`Interval.overlaps`, :meth:`IntervalArray.overlaps`, and :meth:`IntervalIndex.overlaps` for determining overlaps between interval-like objects (:issue:`21998`)
 - :meth:`Timestamp.tz_localize`, :meth:`DatetimeIndex.tz_localize`, and :meth:`Series.tz_localize` have gained the ``nonexistent`` argument for alternative handling of nonexistent times. See :ref:`timeseries.timezone_nonexsistent` (:issue:`8917`)
+- :meth:`Styler.pipe` method added, to simplify application of user-defined functions that operate on stylers.
 
 .. _whatsnew_0240.api_breaking:
 

pandas/io/formats/style.py

@@ -1222,6 +1222,35 @@ class MyStyler(cls):
 
         return MyStyler
 
+    def pipe(self, func, *args, **kwargs):
+        """
+        Apply func(self, *args, **kwargs)
+
+        Parameters
+        ----------
+        func : function
+            function to apply to the Styler.
+            ``args``, and ``kwargs`` are passed into ``func``.
+            Alternatively a ``(callable, data_keyword)`` tuple where
+            ``data_keyword`` is a string indicating the keyword of
+            ``callable`` that expects the Styler.
+        args : iterable, optional
+            positional arguments passed into ``func``.
+        kwargs : mapping, optional
+            a dictionary of keyword arguments passed into ``func``.
+
+        Returns
+        -------
+        result : the value returned by ``func``.
+
+        See Also
+        --------
+        Styler.apply
+        Styler.applymap
+        pandas.DataFrame.pipe
+        """
+        return com._pipe(self, func, *args, **kwargs)
+
 
 def _is_visible(idx_row, idx_col, lengths):
     """

pandas/tests/io/formats/test_style.py

@@ -1173,6 +1173,25 @@ def test_hide_columns_mult_levels(self):
         assert ctx['body'][1][2]['is_visible']
         assert ctx['body'][1][2]['display_value'] == 3
 
+    def test_pipe(self):
+        def set_caption_from_template(styler, a, b):
+            return styler.set_caption(
+                'Dataframe with a = {a} and b = {b}'.format(a=a, b=b))
+        styler = self.df.style.pipe(set_caption_from_template, 'A', b='B')
+        assert 'Dataframe with a = A and b = B' in styler.render()
+
+        def f(s, *args, **kwargs):
+            return s, args, kwargs
+
+        result = self.df.style.pipe(f, 0, a=1)
+        assert result[1] == (0,)
+        assert result[2] == dict(a=1)
+
+        def g(**kwargs):
+            assert 'styler' in kwargs
+            return kwargs['styler'].data
+        assert self.df.style.pipe((g, 'styler')) is self.df
+
 
 @td.skip_if_no_mpl
 class TestStylerMatplotlibDep(object):