Question about mapping x-axis values in matplotlib

Question

I am starting to use the matplotlib library to generate simple graphs. In one of my tests something happens to me that does not allow me to obtain the graph that I expect. Coming to the point, I have two value arrays (circle and g) and I would like to join each of their values. The problem comes when I input the x-axis values. I would like only the values of my array g to be on the x axis, but the following happens:

In my code I have the following:

 import matplotlib.pyplot as plt
 import numpy as np

 fig, ax = plt.subplots()

 circle = [0.002,0.013,0.035]
 g = [5,25,50]
 ax.scatter(g[0], circle[0], color = 'g', marker = "o")

 x = np.array([0,1,2,3])
 my_xticks = [0,5,25,50]

 plt.xticks(x, my_xticks)
 
 plt.show()

Could someone help me fix this?

If you try to disable `# plt.xticks(x, my_xticks)`, you will understand it better: the ticks on the x-axis do not match the tick names. — r-beginners, Nov 19 '21 at 09:30
Try changing `x` to the same values to be the same as `my_xticks` and add an extra line `ax.set_xlim(0,50)`. For reference https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.xticks.html — Abdur Rakib, Nov 19 '21 at 09:30
Both solutions are correct but I'm only interested in getting [0,5,25,50] on the x axis — Carles Sastre Pérez, Nov 19 '21 at 09:37

score 0 · Accepted Answer · answered Nov 19 '21 at 10:26

The problem was that when calling plt.xticks(), you passed [0, 1, 2, 3] as the x-tick values, and you passed the tick values you really wanted as the tick labels. Instead, pass the tick values you want as the first argument, and omit the second argument. The tick labels will be strings of the tick values by default.

import matplotlib.pyplot as plt

circle = [0.002, 0.013, 0.035]
g = [5, 25, 50]
my_xticks = [0] + g

fig, ax = plt.subplots()
ax.scatter(g, circle, color='g', marker='o')
plt.xticks(my_xticks)
plt.show()

Question about mapping x-axis values in matplotlib

1 Answers1