Re: Data Help
- To: mathgroup at yoda.ncsa.uiuc.edu
- Subject: Re: Data Help
- From: "Charles W. Fletcher" <cwf at lakisis.umd.edu>
- Date: Tue, 12 Feb 91 11:13:37 EST
I assume that you are using something like
Plot[F[x],{x,a,b}]
and you want to obtain the associated data (ascii) file of x-y
values that were plotted. These data are in a list in the graphics.
You may see it by using
FullForm[Plot[...]]
To get at the list you need to find it position and use the double
bracket [[ ]] to separate it (See docs on lists of lists and on
expressions.)
Thus if
u = Plot[F[x]...]
then (if I remember correctly)
u[[1,1,1,1,1]]
is the list of data. This varies from plot type to plot type,
so you may need to play around. For example, if
u = Plot3D[...]
then
u[[1]]
is the list of data. If you have problems, contact me and I'll pull
out some of my old notebooks were I did this.
One other thing, I talked to one of the WRI people and he (Kevin
McIssac) noted the following. Due to the algorithm M. uses to plot
the data values (ie, the x-values) may NOT (ie, are most likely not)
evenly spaced. If this is what you want, okay. If not, you should use
Table[] to generate the data.
Good luck,
Charlie