如何使用 matplotlib 绘制数组中的特定点？

Question

I generated two arrays with 10 different values. How do I plot 3 specific values within each array using matplotlib? Here is my code so far:

import numpy as np
import matplotlib as plt
x = np.array(1,2,3,4,5,6,7,8,9,10)
y = np.array(1,2,3,4,5,6,7,8,9,10)

I only want to plot the points 3,4,5 of the x-array and it's corresponding y values. I have tried this:

plt.plot(x[2,3,4], y[2,3,4])
plt.show()

But I get the error "too many indices for array." However, if I write

plt.plot(x[2], y[2])
plt.show()

the second element in the arrays will plot.

Answer 1

The problem is the syntax of x[3, 4, 5] . It is wrong what you want to do is x[3] , x[4] , x[5] , which are the respective elements of the array.

print(x[3], x[4], x[5]) # print 4, 5, 6

A more comfortable way to do this is:

plt.plot(x[2:5], y[2:5])
plt.show()

Where x[2:5] returns from the third to the fifth element.

As Tony Tannous says, the creation of the array is also wrong. np.array needs a list!

Then you also have to change the creation of x and y:

x = np.array([1,2,3,4,5,6,7,8,9,10])
y = np.array([1,2,3,4,5,6,7,8,9,10])

Adding [ and ] to make it a list.

Surely you should see the documentation of Indexing