I have following codes:
#1
axes[0].plot(x,y, color='blue', ls='>')
#2
axes[0].plot(x,y, color='blue', ls='--')
Why code #2 gives me a dashed line, however, #1 does not give triangles?
ls styles can be found here: https://matplotlib.org/2.1.1/api/_as_gen/matplotlib.pyplot.plot.html
Matplotlib's plot() function lets you control the linestyle as well as the marker. If you notice, the styles webpage you provided (https://matplotlib.org/2.1.1/api/_as_gen/matplotlib.pyplot.plot.html) provides characters for line styles and for markers.
You can pass these as separate arguments to plot():
axes[0].plot(x, y, ls='--', marker='>')
Or you can combine them into a single format string:
axes[0].plot(x, y, '-->')
Or just plot the markers or line on their own:
axes[0].plot(x, y, '--') # line only
axes[0].plot(x, y, '>') # markers only