gnuplot-info

[Gnuplot-info] Storing point from data file in variable

[Jeremy C. <jer...@gm...>]

I have a file containing all my data.  I can  easily plot that data.  I need
to store the first data point in a particular column so I can place a label
at that point.  Can someone show me how to do this?
Small example:
# ----------------------------------
x1 = # Get data from file
y1 = 1.0

set label "Hello" at x1, y1 right
# -----------------------------------

Thanks,
Jeremy

Re: [Gnuplot-info] Storing point from data file in variable

[Thomas S. <t.s...@fz...>]

get 1st data of column 3:

x1 = system("head -n1 datafilename | cut -d ' ' -f 3")
or
x1 = system("head -n1 ts.dat | awk '{print $3}'")

or with gnuplot 4.3-cvs:

set table
plot 'datafilename' us 0:($0==0?(x1=$3):$3)
unset table


Jeremy Conlin wrote:
> 
> I have a file containing all my data.  I can  easily plot that data.  I
> need
> to store the first data point in a particular column so I can place a
> label
> at that point.  Can someone show me how to do this?
> Small example:
> # ----------------------------------
> x1 = # Get data from file
> y1 = 1.0
> 
> set label "Hello" at x1, y1 right
> # -----------------------------------
> 
> Thanks,
> Jeremy
> ------------------------------------------------------------------------------
> OpenSolaris 2009.06 is a cutting edge operating system for enterprises 
> looking to deploy the next generation of Solaris that includes the latest 
> innovations from Sun and the OpenSource community. Download a copy and 
> enjoy capabilities such as Networking, Storage and Virtualization. 
> Go to: http://p.sf.net/sfu/opensolaris-get
> _______________________________________________
> Gnuplot-info mailing list
> Gnu...@li...
> https://lists.sourceforge.net/lists/listinfo/gnuplot-info
> 
> 

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Re: [Gnuplot-info] Storing point from data file in variable

[Jeremy C. <jer...@gm...>]

On Thu, Jun 4, 2009 at 5:06 AM, Thomas Sefzick <t.s...@fz...>wrote:

>
> get 1st data of column 3:
>
> x1 = system("head -n1 datafilename | cut -d ' ' -f 3")
> or
> x1 = system("head -n1 ts.dat | awk '{print $3}'")
>
> or with gnuplot 4.3-cvs:
>
> set table
> plot 'datafilename' us 0:($0==0?(x1=$3):$3)
> unset table
>
I do have gnuplot 4.3 and that command sets x1 to the value I want.  But
it's rather cryptic.  Can you tell me what everything means or point me
toward the documentation explaining it?

Thanks,
Jeremy

Re: [Gnuplot-info] Storing point from data file in variable

[Thomas S. <t.s...@fz...>]

starting with gnuplot 4.3-cvs there are new operators
'=' and ',' in expression syntax, that means, one can use
them for the 'using' modifier inside a 'plot' command.

defining labels must be done before plotting, but access
to the data you don't have before plotting, so filling a variable
with some value from the datafile can only be done
when plotting (but then it's too late to define a label).

one solution is to do a dummy plot by plot 'nothing to
nowhere', by doing this you can set the variable.
(plotting to nowhere can be done by specifying
'set out "/dev/null"' on unix systems, or, plotting
nothing can be done by printing a table to
the terminal window or text window)
then you define the title, label, ....
and afterwards you do the real plot.

gnuplot> set table
gnuplot> plot 'datafilename' us 0:($0==0?(x1=$3):$3)
gnuplot> unset table

for explanation of the syntax see
gnuplot> help table
gnuplot> help ternary
gnuplot> help using
gnuplot> help using pseudocolumns


Jeremy Conlin wrote:
> 
> On Thu, Jun 4, 2009 at 5:06 AM, Thomas Sefzick
> <t.s...@fz...>wrote:
> 
>>
>> get 1st data of column 3:
>>
>> x1 = system("head -n1 datafilename | cut -d ' ' -f 3")
>> or
>> x1 = system("head -n1 ts.dat | awk '{print $3}'")
>>
>> or with gnuplot 4.3-cvs:
>>
>> set table
>> plot 'datafilename' us 0:($0==0?(x1=$3):$3)
>> unset table
>>
> I do have gnuplot 4.3 and that command sets x1 to the value I want.  But
> it's rather cryptic.  Can you tell me what everything means or point me
> toward the documentation explaining it?
> 
> Thanks,
> Jeremy
> ------------------------------------------------------------------------------
> OpenSolaris 2009.06 is a cutting edge operating system for enterprises 
> looking to deploy the next generation of Solaris that includes the latest 
> innovations from Sun and the OpenSource community. Download a copy and 
> enjoy capabilities such as Networking, Storage and Virtualization. 
> Go to: http://p.sf.net/sfu/opensolaris-get
> _______________________________________________
> Gnuplot-info mailing list
> Gnu...@li...
> https://lists.sourceforge.net/lists/listinfo/gnuplot-info
> 
> 

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Re: [Gnuplot-info] Storing point from data file in variable

[Jeremy C. <jer...@gm...>]

On Thu, Jun 4, 2009 at 11:57 AM, Thomas Sefzick <t.s...@fz...>wrote:

>
> starting with gnuplot 4.3-cvs there are new operators
> '=' and ',' in expression syntax, that means, one can use
> them for the 'using' modifier inside a 'plot' command.
>
> defining labels must be done before plotting, but access
> to the data you don't have before plotting, so filling a variable
> with some value from the datafile can only be done
> when plotting (but then it's too late to define a label).
>
> one solution is to do a dummy plot by plot 'nothing to
> nowhere', by doing this you can set the variable.
> (plotting to nowhere can be done by specifying
> 'set out "/dev/null"' on unix systems, or, plotting
> nothing can be done by printing a table to
> the terminal window or text window)
> then you define the title, label, ....
> and afterwards you do the real plot.
>
> gnuplot> set table
> gnuplot> plot 'datafilename' us 0:($0==0?(x1=$3):$3)
> gnuplot> unset table
>
> for explanation of the syntax see
> gnuplot> help table
> gnuplot> help ternary
> gnuplot> help using
> gnuplot> help using pseudocolumns


Thank you for that great information.  I'll look up those help topics and if
I have any questions, I'll post them here.

Jeremy