Elegantly changing the color of a plot frame in matplotlib

This is a kind of follow-up question to this post, where the coloring of axes, ticks and labels was discussed. I hope it is alright to open a new, extended question for this.

Changing the color of a complete frame (ticks and axes) around a double-plot (via add_subplot) with axes [ax1, ax2] results in a lot of code. This snippet changes the color of the frame of the upper plot:

ax1.spines['bottom'].set_color('green')
ax1.spines['top'].set_color('green')
ax1.spines['left'].set_color('green')
ax1.spines['right'].set_color('green')
for t in ax1.xaxis.get_ticklines(): t.set_color('green')
for t in ax1.yaxis.get_ticklines(): t.set_color('green')
for t in ax2.xaxis.get_ticklines(): t.set_color('green')
for t in ax2.yaxis.get_ticklines(): t.set_color('green')

So for changing the frame color of two plots with two y-axes each, I would need 16(!) lines of code… This is how it looks like:

Other methods I dug up so far:

• matplotlib.rc: discussed here; changes globally, not locally. I want to have some other plots in different colors. Please, no discussions about too many colors in plots… :-)

  matplotlib.rc('axes',edgecolor='green')
  

• dig out the spines of the axis, then change it: also discussed here; not really elegant, I think.

  for child in ax.get_children():
      if isinstance(child, matplotlib.spines.Spine):
          child.set_color('#dddddd')
  

Is there an elegant way of condensing the above block, something more “pythonic”?

I’m using python 2.6.5 with matplotlib 0.99.1.1 under ubuntu.

Answer

Refactoring your code above:

import matplotlib.pyplot as plt

for ax, color in zip([ax1, ax2, ax3, ax4], ['green', 'green', 'blue', 'blue']):
    plt.setp(ax.spines.values(), color=color)
    plt.setp([ax.get_xticklines(), ax.get_yticklines()], color=color)