[Matplotlib-users] plot(x,y) Trouble?

[Wayne W. <sie...@sb...>]

I find this puzzling. It seems as though the x,y points in some fashion 
can vary.

plot(2.8,3.4) doesn't work in my program
plot([2.8],[3.4]) does work
plot((2.8,3.4)) apparently creates two points

Here's code where I have had to make x,y each a list. I've made comments 
about the behavior of x,y

         fig = figure()
         ax1 = fig.add_subplot(111)
         v = (0, 640, 0, 480)        # min, max on x and y
         ax1.plot(xy[:,0], xy[:,1])   # draw all the lines
         title(afname)
         ylabel('vertical pixels')
         xlabel('horizontal pixels')
         # An attempt to draw an easy large circle. It worked, but zoom 
moves the circle. 320,235 not locked
         # If use (320,235), then get two circles.
         #    ax1.plot([320],[235], marker='o', mfc='y', ms=400)   # 
draw large circle
         ax1.plot([xy[0,0]],[xy[0,1]],'gs')  # place marker at start.   
Had to "list-ize" array columns, but seems right
         ax1.plot([xy[npts-1,0]], [xy[npts-1,1]],'rs') # mark it is a 
last frame. More list-izing, but seems right
         ax1.plot([xy[k_max,0]], [xy[k_max,1]], marker='+', mec='g', 
ms=15) # mark maximum dist frame. Same listizing
         # Next is required for what I'm pretty sure are float64 numbers
         ax1.plot([amax_x], [amax_y], marker='o', mec='m',ms=5) # mark 
max amplitude.
         ax1.axis(v)
         show()

I think the zoom difficulty can be handled with patches. An area I have 
yet to probe.

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