.. _subplots_axes_and_figures-fahrenheit_celsius_scales: subplots_axes_and_figures example code: fahrenheit_celsius_scales.py ==================================================================== .. plot:: /home/tcaswell/other_source/matplotlib/doc/mpl_examples/subplots_axes_and_figures/fahrenheit_celsius_scales.py :: """ Demo of how to display two scales on the left and right y axis. This example uses the Fahrenheit and Celsius scales. """ import matplotlib.pyplot as plt import numpy as np def fahrenheit2celsius(temp): """ Returns temperature in Celsius. """ return (5. / 9.) * (temp - 32) def convert_ax_c_to_celsius(ax_f): """ Update second axis according with first axis. """ y1, y2 = ax_f.get_ylim() ax_c.set_ylim(fahrenheit2celsius(y1), fahrenheit2celsius(y2)) ax_c.figure.canvas.draw() fig, ax_f = plt.subplots() ax_c = ax_f.twinx() # automatically update ylim of ax2 when ylim of ax1 changes. ax_f.callbacks.connect("ylim_changed", convert_ax_c_to_celsius) ax_f.plot(np.linspace(-40, 120, 100)) ax_f.set_xlim(0, 100) ax_f.set_title('Two scales: Fahrenheit and Celsius') ax_f.set_ylabel('Fahrenheit') ax_c.set_ylabel('Celsius') plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)