| Re: i don't see how to summarize it into an object name... :) [message #68109 is a reply to message #68108] |
Thu, 17 September 2009 09:29  |
penteado
Messages: 866
Registered: February 2018
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Senior Member
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On Sep 17, 12:56 pm, "Thibault ." <garthalg...@yahoo.fr> wrote:
> Hi,
>
> In a routine, I have created arrays named arr_1, arr_2 and arr_3.
> I saved them in a file in myfile.sav.
>
> Then when I restore the file, I want to plot my different arrays.
>
> Since i am lazy I would like to make a for loop to do the plots
> (actually thats because i have more than 3 arrays...) but how can I
> call at each iteration the arrays?
>
> To illustrate what i'd like to do is:
>
> for i=1,3 then begin
>
> plot,arr_i
>
> endfor
>
> Of course it does not work but its to show the idea...
>
> Is there a simple way to handle this?
> thanks
There are two simple ways: pointers and structures.
With pointers, you make a pointer array. Then when you create each of
your arrays, you make a copy of it to store in the target of one
element of that pointer array. Something like:
parr=ptrarr(3)
for i=0,2 do begin
*do stuff to make i-th array, into an array called arr*
parr[i]=arr
endfor
Then when you restore it, you can plot all of them with:
for i=0,2 do plot,*parr[i]
With pointers each array is found by an index into the pointer array.
If the number is small and they represent different things, it might
be more convenient to use a structure, so that they also get
associated with names. For instance, say you have 3 arrays called
temperature, pressure, and density:
sarr={temperature:temperature,pressure:pressure,density:dens ity}
Then they could be plotted with
names=tag_names(sarr)
for i=0,n_elements(names)-1 do plot,sarr.(i),title=names[i]
Which would save you from keeping track of which index is which
variable. And you could also access things by their names directly, as
in plot,sar.temperatures. But if you have a large number of arrays of
similar content (say, temperature values resulting from different
sources), a pointer array is more likely to be nicer.
For more complicated structures it may be easier to use the function
create_struct.
Either way, this was assuming that you can go back to the program that
made the save file, and make the pointer array or the structure to put
into the save file. If that is not the case, the nicest way probably
is to use Craig Markwardt's cmrestore, which can give you the contents
of a save file in a pointer array or in a structure:
http://cow.physics.wisc.edu/~craigm/idl/cmsave.html
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