Improve docs regarding plt.close().

anntzer · anntzer · commit be527dc3947b · 2025-03-31T13:11:05.000+02:00
diff --git a/doc/users/faq.rst b/doc/users/faq.rst
@@ -287,6 +287,7 @@ the desired format::
     import matplotlib.pyplot as plt
     plt.plot([1, 2, 3])
     plt.savefig('myfig.png')
+    plt.close()
 
 .. seealso::
 
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -1172,7 +1172,7 @@ def disconnect(cid: int) -> None:
 
 def close(fig: None | int | str | Figure | Literal["all"] = None) -> None:
     """
-    Close a figure window.
+    Close a figure window, and unregister it from pyplot.
 
     Parameters
     ----------
@@ -1185,6 +1185,11 @@ def close(fig: None | int | str | Figure | Literal["all"] = None) -> None:
         - ``str``: a figure name
         - 'all': all figures
 
+    Note
+    ----
+    pyplot maintains a reference to figures created with `figure()` until they
+    are `close()`\ d.  Closing figures is thus necessary to prevent running out
+    of memory (see also :rc:`figure.max_open_warning`).
     """
     if fig is None:
         manager = _pylab_helpers.Gcf.get_active()
