Hi All
> I am new to Matplotlib, and was wondering if anybody knew
> of an easy way to construct a dropline from a data point in
> a plot to the x axis, i.e. a vertical line from (x1,y1) to
> (x1,0)?
ax.plot((x1, x1), (y1, 0), linestyle='-', color='black', linewidth=2)
should do it... There are some helper functions vline and
axvline you may want to look at
http://matplotlib.sourceforge.net/matplotlib.pylab.html#-axvline
http://matplotlib.sourceforge.net/matplotlib.pylab.html#-vline
The first will draw a vertical line that spans the axes vertical
extent regardless of zoom level, and the second simply draws a
vertical line at a given x from y1 to y2. vline supports many
vertical lines and for a single one as in your example, it's easy
enough to just use plot.
JDH