How to plot additional points on the top of scatter plot?

Question

I have panda dataframe as df with two attributes df.one (=x) and df.two (=y). Now, I want to plot scatter plot for these data points. I used

ax1 = fig.add_subplot(111)
ax1.scatter(df.one,df.two,c = 'g',marker = 'o',alpha = 0.2)

Now, I want to plot centroid of the data points give by C. How should I overlay centroid on the above scatter plot? I tried:

ax1.scatter(C[:,0],C[:,1],c = 'r',marker = 'x')

But it overrides the scatter plot, I want to overlay on that. Is there any hold on option, similar to matlab?

Answer 1

If you need points overlaid on the original plot, use

ax.plot(x, y)

ex.

ax = plt.subplot(1, 1, 1)
ax.scatter([1, 2, 3], [1, 2, 3])
ax.plot(1.5, 1.5, "or")

if you pass a list to x and y, multiple points can be added to the plot. Also in case you need to add some annotation beside the point, try

ax.annotate("Some explanation", x, y)

Answer 2

from matplotlib import pyplot as plt
from statistics import *

bill = [34.00, 108.00, 64.00, 88.00, 99.00, 51.00]
tip = [ 5.00,  17.00,  11.00, 8.00,  14.00, 5.00]

bill.sort()
tip.sort()

print(mean(bill))
print(mean(tip))
plt.scatter(bill, tip)
plt.scatter([mean(bill)], [mean(tip)])
plt.show()

I wanted to plot the mean of the data too, so I used this format and got this result:

Result of data