Make functions param to secondary_x/yaxis not keyword-only.

anntzer · anntzer · commit ee4f8c73f483 · 2024-04-24T22:23:25.000+02:00
I suspect the parameter was made keyword-only because the originally
planned signature was `secondary_xaxis(location, forward=...,
inverse=...)` where the keywords actually add some semantics (though
that signature overall seems worse); however, for a single `functions`
parameter, having to type an extra `functions=` in the call doesn't help
the reader much (either they know what secondary_x/yaxis does, in which
case the explicit kwarg doesn't matter, or they don't, in which case the
kwarg name hardly helps)... and is a bit annoying.  See the modified
gallery entry, for example.
diff --git a/galleries/users_explain/quick_start.py b/galleries/users_explain/quick_start.py
@@ -496,7 +496,7 @@ def my_plotter(ax, data1, data2, param_dict):
 
 ax3.plot(t, s)
 ax3.set_xlabel('Angle [rad]')
-ax4 = ax3.secondary_xaxis('top', functions=(np.rad2deg, np.deg2rad))
+ax4 = ax3.secondary_xaxis('top', (np.rad2deg, np.deg2rad))
 ax4.set_xlabel('Angle [°]')
 
 # %%
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -570,7 +570,7 @@ def indicate_inset_zoom(self, inset_ax, **kwargs):
         return self.indicate_inset(rect, inset_ax, **kwargs)
 
     @_docstring.dedent_interpd
-    def secondary_xaxis(self, location, *, functions=None, transform=None, **kwargs):
+    def secondary_xaxis(self, location, functions=None, *, transform=None, **kwargs):
         """
         Add a second x-axis to this `~.axes.Axes`.
 
@@ -624,7 +624,7 @@ def invert(x):
         return secondary_ax
 
     @_docstring.dedent_interpd
-    def secondary_yaxis(self, location, *, functions=None, transform=None, **kwargs):
+    def secondary_yaxis(self, location, functions=None, *, transform=None, **kwargs):
         """
         Add a second y-axis to this `~.axes.Axes`.
 
