How to draw vertical lines on a given plot in matplotlib

Question

Given a plot of signal in time representation, how to draw lines marking corresponding time index?

Specifically, given a signal plot with time index ranging from 0 t

Answer 1

For multiple lines

xposition = [0.3, 0.4, 0.45]
for xc in xposition:
    plt.axvline(x=xc, color='k', linestyle='--')