Remove use_line_collection argument to stem

Author: oscargus

lib/matplotlib/axes/_axes.py

@@ -2886,9 +2886,8 @@ def broken_barh(self, xranges, yrange, **kwargs):
         return col
 
     @_preprocess_data()
-    @_api.delete_parameter("3.6", "use_line_collection")
     def stem(self, *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
-             label=None, use_line_collection=True, orientation='vertical'):
+             label=None, orientation='vertical'):
         """
         Create a stem plot.
 
@@ -2932,8 +2931,8 @@ def stem(self, *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
             cycle.
 
             Note: Markers specified through this parameter (e.g. 'x') will be
-            silently ignored (unless using ``use_line_collection=False``).
-            Instead, markers should be specified using *markerfmt*.
+            silently ignored. Instead, markers should be specified using
+            *markerfmt*.
 
         markerfmt : str, optional
             A string defining the color and/or shape of the markers at the stem
@@ -2953,14 +2952,6 @@ def stem(self, *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
         label : str, default: None
             The label to use for the stems in legends.
 
-        use_line_collection : bool, default: True
-            *Deprecated since 3.6*
-
-            If ``True``, store and plot the stem lines as a
-            `~.collections.LineCollection` instead of individual lines, which
-            significantly increases performance.  If ``False``, defaults to the
-            old behavior of using a list of `.Line2D` objects.
-
         data : indexable object, optional
             DATA_PARAMETER_PLACEHOLDER
 
@@ -3024,27 +3015,12 @@ def stem(self, *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
         basestyle, basemarker, basecolor = _process_plot_format(basefmt)
 
         # New behaviour in 3.1 is to use a LineCollection for the stemlines
-        if use_line_collection:
-            if linestyle is None:
-                linestyle = mpl.rcParams['lines.linestyle']
-            xlines = self.vlines if orientation == "vertical" else self.hlines
-            stemlines = xlines(
-                locs, bottom, heads,
-                colors=linecolor, linestyles=linestyle, label="_nolegend_")
-        # Old behaviour is to plot each of the lines individually
-        else:
-            stemlines = []
-            for loc, head in zip(locs, heads):
-                if orientation == 'horizontal':
-                    xs = [bottom, head]
-                    ys = [loc, loc]
-                else:
-                    xs = [loc, loc]
-                    ys = [bottom, head]
-                l, = self.plot(xs, ys,
-                               color=linecolor, linestyle=linestyle,
-                               marker=linemarker, label="_nolegend_")
-                stemlines.append(l)
+        if linestyle is None:
+            linestyle = mpl.rcParams['lines.linestyle']
+        xlines = self.vlines if orientation == "vertical" else self.hlines
+        stemlines = xlines(
+            locs, bottom, heads,
+            colors=linecolor, linestyles=linestyle, label="_nolegend_")
 
         if orientation == 'horizontal':
             marker_x = heads

lib/matplotlib/pyplot.py

@@ -2922,14 +2922,10 @@ def stackplot(
 @_copy_docstring_and_deprecators(Axes.stem)
 def stem(
         *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
-        label=None,
-        use_line_collection=_api.deprecation._deprecated_parameter,
-        orientation='vertical', data=None):
+        label=None, orientation='vertical', data=None):
     return gca().stem(
         *args, linefmt=linefmt, markerfmt=markerfmt, basefmt=basefmt,
-        bottom=bottom, label=label,
-        use_line_collection=use_line_collection,
-        orientation=orientation,
+        bottom=bottom, label=label, orientation=orientation,
         **({"data": data} if data is not None else {}))
 
 

lib/matplotlib/tests/test_axes.py

@@ -4047,23 +4047,15 @@ def test_hist_stacked_weighted():
     ax.hist((d1, d2), weights=(w1, w2), histtype="stepfilled", stacked=True)
 
 
-@pytest.mark.parametrize("use_line_collection", [True, False],
-                         ids=['w/ line collection', 'w/o line collection'])
 @image_comparison(['stem.png'], style='mpl20', remove_text=True)
-def test_stem(use_line_collection):
+def test_stem():
     x = np.linspace(0.1, 2 * np.pi, 100)
 
     fig, ax = plt.subplots()
     # Label is a single space to force a legend to be drawn, but to avoid any
     # text being drawn
-    if use_line_collection:
-        ax.stem(x, np.cos(x),
-                linefmt='C2-.', markerfmt='k+', basefmt='C1-.', label=' ')
-    else:
-        with pytest.warns(MatplotlibDeprecationWarning, match='deprecated'):
-            ax.stem(x, np.cos(x),
-                    linefmt='C2-.', markerfmt='k+', basefmt='C1-.', label=' ',
-                    use_line_collection=False)
+    ax.stem(x, np.cos(x),
+            linefmt='C2-.', markerfmt='k+', basefmt='C1-.', label=' ')
     ax.legend()
 
 
@@ -4162,23 +4154,14 @@ def test_stem_dates():
     ax.stem(xs, ys)
 
 
-@pytest.mark.parametrize("use_line_collection", [True, False],
-                         ids=['w/ line collection', 'w/o line collection'])
 @image_comparison(['stem_orientation.png'], style='mpl20', remove_text=True)
-def test_stem_orientation(use_line_collection):
+def test_stem_orientation():
     x = np.linspace(0.1, 2*np.pi, 50)
 
     fig, ax = plt.subplots()
-    if use_line_collection:
-        ax.stem(x, np.cos(x),
-                linefmt='C2-.', markerfmt='kx', basefmt='C1-.',
-                orientation='horizontal')
-    else:
-        with pytest.warns(MatplotlibDeprecationWarning, match='deprecated'):
-            ax.stem(x, np.cos(x),
-                    linefmt='C2-.', markerfmt='kx', basefmt='C1-.',
-                    use_line_collection=False,
-                    orientation='horizontal')
+    ax.stem(x, np.cos(x),
+            linefmt='C2-.', markerfmt='kx', basefmt='C1-.',
+            orientation='horizontal')
 
 
 @image_comparison(['hist_stacked_stepfilled_alpha'])