Re: [Gnuplot-py-users] Having trouble with non-numeric data...

[Michael H. <mh...@al...>]

On 07/25/2012 01:06 PM, Vic Watson wrote:
> Apologies for my neophyte question, but I’m a bit new to gnuplot, and I
> need to get this going this week…
>
> I have a data set of test results. The format is very simple:
>
> Attempted,5
> Passed,4
> Failed,1
> Skipped,0
>
> I’m trying to put this through gnuplot to get a graph of the results –
> specifically, I’m trying to return the image from a mod_python module
> running in Apache.
>
> I’ve got a script that does what I want it to do on the gnuplot command
> line :-
>
> set datafile separator ","
> set yrange [0:]
> set style fill solid
> set terminal gif
> set xrange [-.5:3.5]
> attempted_row(x,y)=(x eq "Attempted") ? y:1/0
> skipped_row(x,y)=(x eq "Skipped") ? y:1/0
> passed_row(x,y)=(x eq "Passed") ? y:1/0
> failed_row(x,y)=(x eq "Failed") ? y:1/0
>
> plot results.txt u ($0):(attempted_row(stringcolumn(1),$2)):xtic(1) w
> boxes lc rgb "blue" ti "Attempted", "" u
> ($0):(skipped_row(stringcolumn(1),$2)):xtic(1) w boxes lc rgb "yellow"
> ti "Skipped", "" u ($0):(passed_row(stringcolumn(1),$2)):xtic(1) w boxes
> lc rgb "green" ti "Passed", "" u
> ($0):(failed_row(stringcolumn(1),$2)):xtic(1) w boxes lc rgb "red" ti
> "Failed
>
> Now I’m not completely sure how this script works – I cribbed it from a
> web page and adjusted it to meet my needs.
>
> I’m trying to get this running from Gnuplot.py – and it doesn’t. I can
> “g.plot(‘results.txt’)”, and I seem to get no response. If I try to put
> the data directly into g.plot, I get “ValueError: setting an array
> element with a sequence”.

The pedestrian way to do this is

     g = Gnuplot.Gnuplot()
     g.set(xrange=(-0.5,3.5), yrange=(0,None))
     g('set datafile separator ","')
     g('set style fill solid')
     ...
     g.plot(
         File(
             'results.txt',
             using='($0):(attempted_row(stringcolumn(1),$2)):xtic(1)',
             with='boxes lc rgb "blue"',
             title='Attempted',
             ),
         File(
             'results.txt',
             using='...',
             ...,
             ),
         ...
         )

The maintainable way would be to read the datafile and pick it apart 
into separate lines using Python, then pass each line as a separate 
Data() object to g.plot().

Michael

-- 
Michael Haggerty
mh...@al...
http://softwareswirl.blogspot.com/