two (or more) graphs in one plot with different x-axis AND y-axis scales in python

Question

I want 3 graphs on one axes object, for example:

#example x- and y-data
x_values1=[1,2,3,4,5]
y_values1=[1,2,3,4,5]

x_values2=[-1000,-800,-600,-400,-200]
y_         


        

Answer 1

You could also standardize the data so it shares the same limits and then plot the limits of the desired second scale "manually". This function standardizes the data to the limits of the first set of points:

def standardize(data):
    for a in range(2):
        span = max(data[0][a]) - min(data[0][a])
        min_ = min(data[0][a])
        for idx in range(len(data)):
            standardize = (max(data[idx][a]) - min(data[idx][a]))/span
            data[idx][a] = [i/standardize + min_ - min([i/standardize 
                            for i in data[idx][a]]) for i in data[idx][a]]
    return data

Then, plotting the data is easy:

import matplotlib.pyplot as plt
data = [[[1,2,3,4,5],[1,2,2,4,1]], [[-1000,-800,-600,-400,-200], [10,20,39,40,50]], [[150,200,250,300,350], [10,20,30,40,50]]]
limits = [(min(data[1][a]), max(data[1][a])) for a in range(2)]

norm_data = standardize(data)

fig, ax = plt.subplots()

for x, y in norm_data:
    ax.plot(x, y)

ax2, ax3 = ax.twinx(), ax.twiny()
ax2.set_ylim(limits[1])
ax3.set_xlim(limits[0])

plt.show()

Since all data points have the limits of the first set of points, we can just plot them on the same axis. Then, using the limits of the desired second x and y axis we can set the limits for these two.