I have a 1-D numpy array, which I want to plot and I wanted the plot marker to be a number which shows the location of the element. For example, if my array is `[2.5,4,3]` then I want the plot to have the number 0 at the point (0,2.5), 1 at (1,4) and 2 at (2,3) and so on.

How to do this?