python - Plotting a second scaled y axis in matplotlib from one set of data -

i have 2 views of same data, calls need have y-axis scaled appropriately first natural y-axis. when plot {x,y} data, left y-axis shows y, right y-axis shows 1/y or other function. not ever want plot {x, f(x)} or {x, 1/y}.

now complicate matters using .plt style of interaction rather axis method.

plt.scatter(x, y, c=colours[count], alpha=1.0, label=chart, lw = 0) plt.ylabel(y_lbl) plt.xlabel(x_lbl) 

is there way - plt? or case of generating 2 overlain plots , changing alpha appropriately?

i had check previous (duplicate) question , comments understand want. secondary y-axis can still use twinx. can use set_ylim make sure has same limits first. put tick labels according function (in case 1/y) can use custom funcformatter.

import matplotlib.pyplot plt import numpy np import matplotlib.ticker mticker  fig, ax1 = plt.subplots(1,1) ax1.set_xlabel('x') ax1.set_ylabel('y')  # plot x = np.linspace(0.01, 10*np.pi, 1000) y = np.sin(x)/x ax1.plot(x, y)  # add twin axes , set limits matches first ax2 = ax1.twinx() ax2.set_ylabel('1/y') ax2.set_ylim(ax1.get_ylim())  # apply function formatter formatter = mticker.funcformatter(lambda x, pos: '{:.3f}'.format(1./x)) ax2.yaxis.set_major_formatter(formatter)  plt.show() 

result: