Re: How to use table header as title inside for loops?

[James R. V. Z. <jr...@co...>]

Ethan Merritt wrote:
> On Thursday 12 March 2009, Juergen Wieferink wrote:
> I have [...] modified the parsing code, which now accepts:
>     plot ...  title columnheader
>     plot ...  title columnheader(N)
> The option is now handled by the normal title parsing code, so there is
> no strangeness with the order of title options on the command line.
>
> The original form of the command, which was never documented but was 
> used in several of the demos, is now deprecated.  However it still works
> if you ./configure --enable-backwards-compatibility
> Thus
>    plot ... using 1 title 1 
> should be re-written using any of the following:
>    plot ... using 1 title col
>    plot ... using 1 title columnhead(1)
>    set key autotitle columnhead
>    plot ... using 1

Suppose I have data that looks like this:

   1.000000 2.000000 2.000000
   2.000000 1.000000 2.000000
   3.000000 0.666667 2.000000
   4.000000 0.500000 2.000000
   
   
   1.000000 3.000000 3.000000
   2.000000 1.500000 3.000000
   3.000000 1.000000 3.000000
   4.000000 0.750000 3.000000
   
   
   1.000000 4.000000 4.000000
   2.000000 2.000000 4.000000
   3.000000 1.333333 4.000000
   4.000000 1.000000 4.000000
   ...
   
I would like to plot each datablock with its own title taken from the
third column.  I can use

  plot for [n=0:3] 'lab.dat' in n title 3

except that the first line of each datablock is not plotted. 

Maybe what I want is

  plot for [n=0:3] 'lab.dat' in n title datastring(3)

but that isn't implemented?


BTW my application is a simulation where several of the columns have
input parameters, and the rest of the columns have outputs.  I can
plot one output as a function of two inputs using splot.  However, to
make it possible to actually read values off the curves, I would like
to plot iso-<whatever> lines: output as a function of one input
parameter, for selected values of a second parameter, and all other
parameters held constant.  It would be very helpful to get the curve
labels from the data file itself.

            - Jim Van Zandt