Handle single color for multiple datasets in hist (matplotlib#30867)

Author: gapplef

doc/release/next_whats_new/hist_color.rst

@@ -0,0 +1,5 @@
+``hist()`` supports a single color for multiple datasets
+--------------------------------------------------------
+
+It is now possible to pass a single *color* value to `~.Axes.hist()`. This
+value is applied to all datasets.

lib/matplotlib/axes/_axes.py

@@ -7326,6 +7326,9 @@ def hist(self, x, bins=None, range=None, density=False, weights=None,
             Color or sequence of colors, one per dataset.  Default (``None``)
             uses the standard line color sequence.
 
+            .. versionadded:: 3.10
+               It is now possible to use a single color with multiple datasets.
+
         label : str or list of str, optional
             String, or sequence of strings to match multiple datasets.  Bar
             charts yield multiple patches per dataset, but only the first gets
@@ -7447,6 +7450,8 @@ def hist(self, x, bins=None, range=None, density=False, weights=None,
         if color is None:
             colors = [self._get_lines.get_next_color() for i in range(nx)]
         else:
+            if mcolors.is_color_like(color):
+                color = [color]*nx
             colors = mcolors.to_rgba_array(color)
             if len(colors) != nx:
                 raise ValueError(f"The 'color' keyword argument must have one "

lib/matplotlib/tests/test_axes.py

@@ -2580,6 +2580,15 @@ def test_hist_zorder(histtype, zorder):
         assert patch.get_zorder() == zorder
 
 
+def test_hist_single_color_multiple_datasets():
+    data = [[0, 1, 2], [3, 4, 5]]
+    _, _, bar_containers = plt.hist(data, color='k')
+    for p in bar_containers[0].patches:
+        assert mcolors.same_color(p.get_facecolor(), 'k')
+    for p in bar_containers[1].patches:
+        assert mcolors.same_color(p.get_facecolor(), 'k')
+
+
 def test_stairs_no_baseline_fill_warns():
     fig, ax = plt.subplots()
     with pytest.warns(UserWarning, match="baseline=None and fill=True"):