I am plotting two similar trajectories in matplotlib and I'd like to plot each of the lines with partial transparency so that the red (plotted second) doesn't obscure the blue.
EDIT: Here's the image with transparent lines.
Plain and simple:
plt.plot(x, y, 'r-', alpha=0.7)
(I know I add nothing new, but the straightforward answer should be visible).
After I plotted all the lines, I was able to set the transparency of all of them as follows:
for l in fig_field.gca().lines: l.set_alpha(.7)
EDIT: please see Joe's answer in the comments.