set alpha channel for pyplot objects?

Question

In R, you can set the alpha channel by

rgb(r=.1,g=.5,b=.5,alpha=.5,max=1)

for any object that takes a color argument. patch objects in pyplot have a set_alpha method, but can this be done for lines on a plot, for instance? like pyplot.plot(x,y,color=???) or h = pyplot.plot(x,y) and do something with h.

Answer 1

plt.plot(x,y,'ro-',alpha=0.3)

if you want to mix up your own color, you can pass a hex value or an rgb tuple http://matplotlib.sourceforge.net/api/colors_api.html