How to plot x versus y lines using matplotlib?

Question

How to plot a x versus y line? By x versus y, I mean how to plot x vs y line if the x and y axes have already fixed, as if the axes are reversed for this line.

Update: Some one asked me why not just reverse the arguments and axes labels. Here is my reason: this x vs y line is only a part of a 2D plot (the main plot) and the main axes are for the 2D plot. What's more, there are also y vs x lines in the same 2D plot. I do this because I want to show certain line clearly.

Update: Here is a example what I want:

I want to plot the black line in the figure which I draw manually (actually I want to draw Gaussian curve). It is time vs voltage. I still want to keep the existed blue line and I should not reverse the time/voltage labels.

You mean you want to reverse the axes? Why don't you just reverse the arguments? ax.plot(s, t) and reverse the time/voltage labels. — Djib2011
– Djib2011, Commented Apr 4, 2018 at 7:13
@Djib2011 Uh, because this x vs y line is only a part of a 2D plot and the axes is for the 2D plot. What's more, there is also y vs x lines in the same 2D plot. I do this because I want to show certain line clearly. — Bettertomo
– Bettertomo, Commented Apr 4, 2018 at 7:59
I ask it because I really need it. In the past I make it using Photoshop, but now I think it is too tricky. I believe it is not only me who need a way to do this. — Bettertomo
– Bettertomo, Commented Apr 4, 2018 at 8:00
Your updated figure shows a flipped x-y axis. This is what Djib2011 suggested. — Mr. T
– Mr. T, Commented Apr 4, 2018 at 8:59
@MrT I feel a little confused. I still want to keep the existed blue line and I should not reverse the time/voltage labels. — Bettertomo
– Bettertomo, Commented Apr 4, 2018 at 9:01

Mr. T · Accepted Answer · 2018-04-04 09:40:26Z

2

You can easily plot multiple curves in the same subplot in matplotlib. As an example see this annotated code:

import matplotlib.pyplot as plt
import numpy as np

# Data for plotting
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2 * np.pi * t)

# Note that using plt.subplots below is equivalent to using
# fig = plt.figure() and then ax = fig.add_subplot(111)
fig, ax = plt.subplots()
#plot sine wave
ax.plot(t, s, label = "sine wave")

#now create y values for the second plot
y = np.linspace(0, 2, 1000)
#calculate the values for the Gaussian curve
x = 2 * np.exp(-0.5 * np.square(-4 * (y - 1)))
#plot the Gaussian curve
ax.plot(x, y, label = "Gaussian curve")

ax.set(xlabel='time (s)', ylabel='voltage (mV)',
       title='About as simple as it gets, folks')
ax.grid()

#show the legend
plt.legend()
plt.show()

Output:

edited Apr 4, 2018 at 9:40

answered Apr 4, 2018 at 9:32

Mr. T

12.5k10 gold badges39 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Bettertomo Over a year ago

I can't believe there is such an elegant way. Thank you! I was confused why people voted down, now I know it.

Mr. T Over a year ago

The main reason for the down-votes was the confusing question. I was not sure that this is, what you try to achieve. Glad we found a solution. Good luck with your project.

Collectives™ on Stack Overflow

How to plot x versus y lines using matplotlib?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related