Re: [Matplotlib-users] instance check, finding figure elements

[John H. <jd...@gm...>]

On Sat, Oct 15, 2011 at 10:39 AM,  <jos...@gm...> wrote:
> I'm building plots in stages using several different functions. Since
> the figure contains all information, I don't hand handles to
> individual elements around.
>
> What's the best way to check for a specific plot element? using
> isinstance, or are there specific attributes that could be checked?

Checkout out Artist.findobj

  http://matplotlib.sourceforge.net/api/artist_api.html#matplotlib.artist.Artist.findobj

Artist is the base class for everything in a matplotlib figure, the
Figure, Axes, Axis, Text, Line2D, Polygon, etc, all derive from
Artist, so you can call this method on any mpl object to recursively
search for objects of a given type.  By recursive, I mean search the
objects children, their children, etc.  See also

    http://matplotlib.sourceforge.net/users/artists.html

for more info on the artist hierarchy.

But for your specific example, each axes has an `images` attribute,
which is a list of images it contains (this is detailed in the artist
tutorial linked above, so you could simplify your code with something
like:

    images = np.concatenate([ax.images for ax in fig.axes])

JDH