plotting markers on top of axes

Question

I am tying to make a (x,y) scatter plot using numpy. Right now the axes start from (0,0) and extend to align with the range of the data. I need to plot two points which lie on

Answer 1

I think you're after plt.axis([xmin,xmax,ymin,ymax]):

import numpy as np
import matplotlib.pyplot as plt
x = np.array([0,1,2,3,4,5,6])
y = np.array([0,2,0,4.5,0.5,2,3])
plt.plot(x,y,'o')
plt.axis()
# (0.0, 6.0, 0.0, 4.5)
plt.axis([-.5,6.5,-.5,5])
plt.show()

You could programatically retrive the current axis with plt.axis() and then subtract/add a small margin on, and re-set it.