[Gnuplot-info] conditional plot

[Mahmood N. <nt_...@ya...>]

Hi
I have a data file which looks like

10 20 M
30 10 H
...

What I want to do is to plot the second column if the third column is 'M'. Is it possible to to do that with a magic command (piping plt with grep) inside the gnuplot? Or I have to do a preprocess on the data file and extract all lines with 'M' value to another file and then plot the new file?

Many thanks for any suggestion.
 
Regards,
Mahmood