Question

What I’m trying to do could be written like this:

import pylab
class GetsDrawn(object):
    def __init__(self):
        self.x=some_function_that_returns_an_array()
        self.y=some_other_function_that_returns_an_array()

    # verison 1: pass in figure/subplot arguments
    def draw(self, fig_num, subplot_args ):
        pylab.figure(fig_num)
        pylab.subplot( *subplot_args )
        pylab.scatter( self.x, self.y)

i.e. I could tell the object “where” to draw itself via a figure-number and sub-plot configuration.

I suspect that a version which is passed a pylab object would be more flexible in the
long run, but don’t know what type of object(s) to provide to the function.

Answer 1

For scripts, it is generally preferred to use the object oriented api.

For example, you can let your function receive a figure:

def draw(fig, sub_plot_args,x,y):
    ax = fig.subplot(*sub_plot_args)
    ax.scatter(x,y)

If your function actually draws only on one axes, you can even pass that as an object:

def draw(ax,x,y):

    ax.scatter(x,y)

To create a figure use:

import matplotlib.pyplot as plt
fig = plt.figure()

and to create for example a figure with one subplot on it, use:

fig, ax = plt.subplots()

The last command only exists in recent versions if I am not mistaken.