draw only vertical bar in python matplotlib code example

Example 1: vertical line in matplotlib

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

Example 2: add vertical line in plot python

pythonCopymatplotlib.pyplot.axvline(x=0, ymin=0, ymax=1, hold=None, **kwargs)