Merge pull request #30459 from rcomer/hat-graph

timhoffm · web-flow · commit a617ece99486 · 2025-08-24T12:38:58.000+02:00
DOC: simplify hat graph example
diff --git a/galleries/examples/lines_bars_and_markers/hat_graph.py b/galleries/examples/lines_bars_and_markers/hat_graph.py
@@ -29,35 +29,28 @@ def hat_graph(ax, xlabels, values, group_labels):
         The group labels displayed in the legend.
     """
 
-    def label_bars(heights, rects):
-        """Attach a text label on top of each bar."""
-        for height, rect in zip(heights, rects):
-            ax.annotate(f'{height}',
-                        xy=(rect.get_x() + rect.get_width() / 2, height),
-                        xytext=(0, 4),  # 4 points vertical offset.
-                        textcoords='offset points',
-                        ha='center', va='bottom')
-
     values = np.asarray(values)
-    x = np.arange(values.shape[1])
-    ax.set_xticks(x, labels=xlabels)
-    spacing = 0.3  # spacing between hat groups
-    width = (1 - spacing) / values.shape[0]
-    heights0 = values[0]
-    for i, (heights, group_label) in enumerate(zip(values, group_labels)):
-        style = {'fill': False} if i == 0 else {'edgecolor': 'black'}
-        rects = ax.bar(x - spacing/2 + i * width, heights - heights0,
-                       width, bottom=heights0, label=group_label, **style)
-        label_bars(heights, rects)
+    color_cycle_colors = plt.rcParams['axes.prop_cycle'].by_key()['color']
+
+    # Draw the hats
+    bars = ax.grouped_bar(
+        (values - values[0]).T, bottom=values[0], tick_labels=xlabels,
+        labels=group_labels, edgecolor='black', group_spacing=0.8,
+        colors=['none'] + color_cycle_colors)
 
+    # Attach a text label on top of each bar
+    for bc, heights in zip(bars.bar_containers, values):
+        ax.bar_label(bc, heights, padding=4)
 
-# initialise labels and a numpy array make sure you have
+
+# Initialise labels and a numpy array make sure you have
 # N labels of N number of values in the array
 xlabels = ['I', 'II', 'III', 'IV', 'V']
 playerA = np.array([5, 15, 22, 20, 25])
 playerB = np.array([25, 32, 34, 30, 27])
 
-fig, ax = plt.subplots()
+fig, ax = plt.subplots(layout='constrained')
+
 hat_graph(ax, xlabels, [playerA, playerB], ['Player A', 'Player B'])
 
 # Add some text for labels, title and custom x-axis tick labels, etc.
@@ -67,7 +60,6 @@ def label_bars(heights, rects):
 ax.set_title('Scores by number of game and players')
 ax.legend()
 
-fig.tight_layout()
 plt.show()
 # %%
 #
@@ -76,8 +68,8 @@ def label_bars(heights, rects):
 #    The use of the following functions, methods, classes and modules is shown
 #    in this example:
 #
-#    - `matplotlib.axes.Axes.bar` / `matplotlib.pyplot.bar`
-#    - `matplotlib.axes.Axes.annotate` / `matplotlib.pyplot.annotate`
+#    - `matplotlib.axes.Axes.grouped_bar` / `matplotlib.pyplot.grouped_bar`
+#    - `matplotlib.axes.Axes.bar_label` / `matplotlib.pyplot.bar_label`
 #
 # .. tags::
 #
