[FIXED] Why can one x value correspond to multiple y values when I use matplotlib?

Issue

I am trying to use matplotlib to draw a curve to represent its changing trend. Here are my code:

import matplotlib.pyplot as plt

x = [3.0589998800678586e-07, 3.575999869553925e-07, 4.17199998992146e-07, 0.9999997019767761, 5.364000230656529e-07]
y = [1509, 108, 99, 88, 85]

plt.plot(x, y)
plt.show()
plt.save("./frequency.png")

Here is the graph I get: picture that I got

There are not any same values. I want to know where is the problem?

Solution

To consolidate the comments, there are two problems here:

1. The x values are not sorted
2. The x values are very small, so on a scale of 0 to 1, the very small x values all appear seeemingly at the same spot.

You can correct #1 by sorting the values:

x, y = zip(*sorted(zip(x, y), key=lambda pair: pair[0]))

By zipping x and y together here for the sort, you are ensuring that all of the coordinate pairs remain the same, they are just ordered separately. You can correct #2 using

plt.xscale("log")

Altogether:

x, y = zip(*sorted(zip(x, y), key=lambda pair: pair[0]))
plt.plot(x, y)
plt.xscale("log")
plt.show()
plt.savefig("frequency.png")

to get

Note: I actually had to remove plt.show() to get the saved figure to not appear blank.

Answered By - Kraigolas