Display numbers instead of points using pyplot

Question

I have a nx2 dimension array representing n points with their two coordinates x, y. Using pyplot, I would like to display the number n of my points instead of just the points with no way to know which is what.

I have found a way to legend my points but really what I would like is only the number.

How can I achieve this ?

Could be a duplicate, however I was interpreting the title and last sentence in the question such that user has already found a solution such as the one from the linked question, but does not like it. Improving the quesiton may help understanding if this is the case or not. — ImportanceOfBeingErnest, Jun 19 '17 at 12:41
It is the case, I would like numbers showing up **instead** of points. — user8182249, Jun 19 '17 at 13:33

ImportanceOfBeingErnest · Accepted Answer · 2017-06-30T09:15:24.703

6

You may use plt.text to place the number as text in the plot. To have the number appear at the exact position of the coordinates, you may center align the text using ha="center", va="center".

import numpy as np; np.random.seed(2)
import matplotlib.pyplot as plt

xy = np.random.rand(10,2)

plt.figure()
for i, ((x,y),) in enumerate(zip(xy)):
    plt.text(x,y,i, ha="center", va="center")

plt.show()

In order to have the plot autoscale to the range where the values are, you may add an invisible scatter plot

x,y =zip(*xy)
plt.scatter(x,y, alpha=0)

or, if numbers are really small, better an invisible plot

x,y =zip(*xy)
plt.plot(x,y, alpha=0.0)

edited Jun 30 '17 at 09:15

answered Jun 19 '17 at 12:21

ImportanceOfBeingErnest

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Thank you ! Your code works for me and this what I want except that I use a normal distribution so I have `xy = np.random.normal(0, 1, (10, 2))` instead and see nothing displayed :/ – user8182249 Jun 19 '17 at 13:31
The values are out of the plotting range. See updated answer. – ImportanceOfBeingErnest Jun 19 '17 at 13:37
The scaling seems to work except for very small values (10^-12). Do you know how to solve this problem ? – user8182249 Jun 30 '17 at 08:55
Which problem ? – ImportanceOfBeingErnest Jun 30 '17 at 08:56
I see. In that case better make an invisible plot instead of a scatter. I updated the answer. – ImportanceOfBeingErnest Jun 30 '17 at 09:15
When I plot points with very small values, I have to zoom many times on a small rectangle where all the points are concentrated before I can actually see the points distinctly. I would like the axes to be scaled to the figure so that I don't have to zoom. – user8182249 Jun 30 '17 at 09:17

Display numbers instead of points using pyplot

1 Answers1

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