gnuplot-info

[Gnuplot-info] get data then calculate and then plot

[Markus F. <fel...@gm...>]

Hey All,

I have got a data file with some values.
Therfor i wanna subtract some pairs of values and then plot them.

But how can i do this?

As I know you can select values in a data file by the "using" command,
but I think there is no possibility to calculate this values before i
plot this?

Any Idea?

mfg Markus

Re: [Gnuplot-info] get data then calculate and then plot

[<br...@ph...>]

Markus Feldmann wrote:

> I have got a data file with some values.
> Therfor i wanna subtract some pairs of values and then plot them.

*Which* pairs to you want to subtract from each other?

> As I know you can select values in a data file by the "using" command,
> but I think there is no possibility to calculate this values before i
> plot this?

If what you're trying to do isn't something like

	plot 'data' using 1:($2-$3)

then gnuplot can't do it (--> 'help using').  In that case, you have to 
do the work outside, in a data preconditioning program, which you can 
then use from inside gnuplot like this

	plot "< program data"

See 'help datafile special'

Re: [Gnuplot-info] get data then calculate and then plot

[fly a. <vic...@gm...>]

Hans-Bernhard Br=C3=B6ker wrote:
>=20
> Markus Feldmann wrote:
>=20
>> I have got a data file with some values.
>> Therfor i wanna subtract some pairs of values and then plot them.
>=20
> *Which* pairs to you want to subtract from each other?
>=20
>> As I know you can select values in a data file by the "using" command,
>> but I think there is no possibility to calculate this values before i
>> plot this?
>=20
> If what you're trying to do isn't something like
>=20
> =09plot 'data' using 1:($2-$3)
>=20
> then gnuplot can't do it (--> 'help using').  In that case, you have to=
=20
> do the work outside, in a data preconditioning program, which you can=20
> then use from inside gnuplot like this
>=20
> =09plot "< program data"
>=20
> See 'help datafile special'
>=20
Couldn't one just write a function and do
f(x,y)=3Dx-y
plot 'file' u 1:(f($2,$3))? It would probably be easier than reformatting
input files

Victor


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-and-then-plot-t1601136.html#a4347300
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Re: [Gnuplot-info] get data then calculate and then plot

[<br...@ph...>]

fly away wrote:
> Hans-Bernhard Bröker wrote:

>> If what you're trying to do isn't something like
>>
>> 	plot 'data' using 1:($2-$3)
>>
>> then gnuplot can't do it (--> 'help using').

> Couldn't one just write a function and do
> f(x,y)=x-y
> plot 'file' u 1:(f($2,$3))? 

Of course one can.  That's well within the boundaries of "something like 
..."