Andreas - Most everyone prefers to use the dotted grid style so I didn't put an explicit option in for that. However after the call to plt you can change the grid to solid with the following command:
Jeff - There is a way to force plt to do something like hold on/off but its messy and I wouldn't recommend it since it is so different from the work flow that I imagined for plt. Perhaps you could let me know what exactly you are trying to plot and I probably can suggest the best way for you to use plt to accomplish that. Also you might peruse the various demo programs for ideas on how best to use plt.
Christine - I'm not sure I understand your question exactly. Perhaps its just that you want to know what a color such as [x y z] looks like? If that's the question, the answer is pretty simple. The 3 numbers are the amount of Red, Green, and Blue in the selected color. (The numbers must be between 0 and 1. Plenty about that in the matlab documentation.) Here is a good way to see what any color selection will look like: In any plot created with plt, enable the menu bar by clicking on the "Menu" tag, then select the last menu ("Color/Lines"). Then select "Edit line". Then in the new figure that appears, RIGHT click on the 3 numbers below the line properties color popup. This will open the color pick window which initially will show you a palette of 256 colors possible with red=0. To see the palette with some other value of red, just move the red slider. Or move the green slider to force that amount of green and see a palette of colors that results. (Same for the blue slider of course). I hope that helps.
17 Apr 2013
A framework for GUI designs with 2D plots.
plot/plotyy alternativ optimized for data exploration.