For single datasets, don't wrap artist added by Axes.hist in silent_list

anntzer · anntzer · commit 470f67f26161 · 2019-03-12T00:30:57.000+01:00
See details in changelog note.
diff --git a/doc/api/next_api_changes/2019-03-11-AL.rst b/doc/api/next_api_changes/2019-03-11-AL.rst
@@ -0,0 +1,32 @@
+When using a single dataset, `Axes.hist` no longer wraps the added artist in a `silent_list`
+````````````````````````````````````````````````````````````````````````````````````````````
+
+When `Axes.hist()` is called with a single dataset, it adds to the axes either
+a `BarCollection` object (when ``histtype="bar"`` or ``"barstacked"``), or a
+`Polygon` object (when ``histype="step"`` or ``"stepfilled"``) -- the latter
+being wrapped in a list-of-one-element.  Previously, either artist would be
+wrapped in a `silent_list`.  This is no longer the case: the `BarCollection` is
+now returned as is (this is an API breaking change if you were directly relying
+on the concrete `list` API; however, `BarCollection` inherits from `tuple` so
+most common operations remain available), and the list-of-one `Polygon` is
+returned as is.  This makes the `repr` of the returned artist more accurate: it
+is now ::
+
+    <BarContainer object of of 10 artists>  # "bar", "barstacked"
+    [<matplotlib.patches.Polygon object at 0xdeadbeef>]  # "step", "stepfilled"
+
+instead of ::
+
+    <a list of 10 Patch objects>  # "bar", "barstacked"
+    <a list of 1 Patch objects>  # "step", "stepfilled"
+
+When `Axes.hist()` is called with multiple artists, it still wraps its return
+value in a `silent_list`, but uses more accurate type information ::
+
+    <a list of 3 BarContainer objects>  # "bar", "barstacked"
+    <a list of 3 List[Polygon] objects>  # "step", "stepfilled"
+
+instead of ::
+
+    <a list of 3 Lists of Patches objects>  # "bar", "barstacked"
+    <a list of 3 Lists of Patches objects>  # "step", "stepfilled"
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -6550,9 +6550,10 @@ def hist(self, x, bins=None, range=None, density=None, weights=None,
             edge of last bin).  Always a single array even when multiple data
             sets are passed in.
 
-        patches : list or list of lists
-            Silent list of individual patches used to create the histogram
-            or list of such list if multiple input datasets.
+        patches : `.BarContainer` or list of a single `.Polygon` or list of \
+such objects
+            Container of individual artists used to create the histogram
+            or list of such containers if there are multiple input datasets.
 
         Other Parameters
         ----------------
@@ -6865,9 +6866,11 @@ def hist(self, x, bins=None, range=None, density=None, weights=None,
                     p.set_label('_nolegend_')
 
         if nx == 1:
-            return tops[0], bins, cbook.silent_list('Patch', patches[0])
+            return tops[0], bins, patches[0]
         else:
-            return tops, bins, cbook.silent_list('Lists of Patches', patches)
+            patch_type = ("BarContainer" if histtype.startswith("bar")
+                          else "List[Polygon]")
+            return tops, bins, cbook.silent_list(patch_type, patches)
 
     @_preprocess_data(replace_names=["x", "y", "weights"])
     @cbook._rename_parameter("3.1", "normed", "density")
