Stopping Repeating Values from Being Plotted

Hey guys,

I am trying to stop repeating values from being plotted in a stress-strain curve. I have an imported excel spreadhseet where I am getting my values from, and at one point the strain values repeat themselves, but I do not want to include them in my plot. Is there a way to do this? I've been fooling around with while loops for a while now and nothing seems to be working.

Thanks!