DOC: demonstrate use of partial in FuncAnimation

rcomer · rcomer · commit c84ccc748bf6 · 2024-01-09T18:03:50.000Z
diff --git a/galleries/examples/animation/animated_histogram.py b/galleries/examples/animation/animated_histogram.py
@@ -7,6 +7,8 @@
 histogram.
 """
 
+import functools
+
 import matplotlib.pyplot as plt
 import numpy as np
 
@@ -24,11 +26,10 @@
 # %%
 # To animate the histogram, we need an ``animate`` function, which generates
 # a random set of numbers and updates the heights of rectangles. The ``animate``
-# function updates the `.Rectangle` patches on a global instance of
-# `.BarContainer` (which in this case is defined below).
+# function updates the `.Rectangle` patches on an instance of `.BarContainer`.
 
 
-def animate(frame_number):
+def animate(frame_number, bar_container):
     # Simulate new data coming in.
     data = rng.standard_normal(1000)
     n, _ = np.histogram(data, HIST_BINS)
@@ -39,7 +40,9 @@ def animate(frame_number):
 
 # %%
 # Using :func:`~matplotlib.pyplot.hist` allows us to get an instance of
-# `.BarContainer`, which is a collection of `.Rectangle` instances.
+# `.BarContainer`, which is a collection of `.Rectangle` instances.  Since
+# `.FuncAnimation` will only pass the frame number parameter to the animation
+# function, we use `functools.partial` to fix the ``bar_container``` parameter.
 
 # Output generated via `matplotlib.animation.Animation.to_jshtml`.
 
@@ -48,7 +51,8 @@ def animate(frame_number):
                               ec="yellow", fc="green", alpha=0.5)
 ax.set_ylim(top=55)  # set safe limit to ensure that all data is visible.
 
-ani = animation.FuncAnimation(fig, animate, 50, repeat=False, blit=True)
+anim = functools.partial(animate, bar_container=bar_container)
+ani = animation.FuncAnimation(fig, anim, 50, repeat=False, blit=True)
 plt.show()
 
 # %%
