使用for循环制作多个Python APLpy子图

Question

I'm trying to create multiple subplots of fits images using APLpy, and I'd like to be able create these through a for loop to prevent me having to type out dozens of parameters multiple times for N plots.

Using an inelegant brute-force method, for N=2 plots it might go like this:

import aplpy
import matplotlib.pyplot as plt

fig = plt.figure()
f1 = aplpy.FITSFigure("figure1.fits", figure=fig, subplot=[0,0,0.5,0.5])
f2 = aplpy.FITSFigure("figure2.fits", figure=fig, subplot=[0.5,0.5,0.5,0.5])
# And there are many more images at this point, but let's look at 2 for now.

f1.show_colorscale()
f1.add_colorbar()
f1.frame.set_linewidth(0.75)
# And many more settings would follow

# Repeat this all again for the second plot
f2.show_colorscale()
f2.add_colorbar()
f2.frame.set_linewidth(0.75)

fig.canvas.draw()
fig.savefig('figure.eps')

But I'd like to replace the two sets of plot parameters with a for loop since many of the other plot parameters are controlled in this way and I'd like to do several more plots. I'd like to replace those lines with something like:

for i in range(1,3):
    f{i}.show_grayscale()
    f{i}.add_colorbar()
    f{i}.frame.set_linewidth(0.75)

etc.

Obviously this syntax is wrong. Essentially I need to be able to modify the code itself in the for loop. I can't find how to do this in Python, but if I were doing something similar in .csh, I might write it as eg f"$i".show_grayscale() .

Thanks.

Answer 1

A way to do it is to add your FITSFigure objects into a list:

fig = plt.figure(figsize=(8,10))
gc = []
gc.append(aplpy.FITSFigure(img1, subplot=[0.05,0.05,0.9,0.3], figure=fig))
gc.append(aplpy.FITSFigure(img2, subplot=[0.05,0.35,0.9,0.3], figure=fig))

then you can iterate with a normal for:

for i in xrange(len(gc)):
  gc[i].recenter(ra, dec, radius=0.5)
  gc[i].tick_labels.hide()
  gc[i].axis_labels.hide()

Answer 2

I was shown the way to the solution to this today. The exec() command lets you execute a string of code in exactly this way. The solution to this particular case would be to use:

for i in range(1,3):
    exec('f' + str(i) + '.show_grayscale()')
    exec('f' + str(i) + '.add_colorbar()')
    exec('f' + str(i) + '.frame.set_linewidth(0.75)')

The downside here is that the code you write inside the string to be executed does not have the colour-coded formatting that it would normally have.