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pythonvariablesmatplotlibaxes

python matplotlib convert string variable to axes attributes

I am not really a python guy. I am coming from Fortran background and trying to understand object-oriented programming, so please forgive me if my questions are silly! I have the following simple piece of code:

#!/usr/bin/env python

import matplotlib.pyplot as plt
import numpy as np


fig = plt.figure(figsize=(6,6))
ax1 = fig.add_axes([0.1,0.1,0.6,0.6])

a = ax1
ya = 'yaxis'

x = np.linspace(0.0, 2.*np.pi)
a.ya.set_ticks_position('left')

a.plot(x,np.sin(x))
plt.show()

Now I want to assign a variable ya the axes attribute yaxis. Obviously 'yaxis' is string so ya will be a string variable. So, my code fails with:

Traceback (most recent call last):
  File "./t.py", line 14, in <module>
    a.ya.set_ticks_position('left')
AttributeError: 'Axes' object has no attribute 'ya'

I see the reason for this (because ya is a string variable and a is a class object and expects an attribute of some data type). My questions is how do you convert the ya = yaxis to a proper variable that a or ax1 will accept. I know in this case it is sort of redundant doing it but eventually I will be looping over many axes and their attributes e.g. (ax1, ax2.......) and xaxis, yaxis and I don't want to have them hard coded. Any help will be very much appreciated!

Solution

  • Check the built-in functions getattr and setattr.

    getattr(object, attrname)
setattr(object, attrname, value)