| Re: i don't see how to summarize it into an object name... :) [message #68085] |
Sun, 20 September 2009 06:05 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Paolo writes:
> PS: I can't offer any excuse for posting this, other
> than it seems this group has become more boring
> in David's absence...
I'm glad someone misses me. My tennis team won the
State Championships while I was gone (always disconcerting),
and we are off to the Sectionals in Idaho this week. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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| Re: i don't see how to summarize it into an object name... :) [message #68090 is a reply to message #68085] |
Fri, 18 September 2009 07:04  |
Jeremy Bailin
Messages: 618
Registered: April 2008
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Senior Member |
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On Sep 17, 3:32 pm, Paolo <pgri...@gmail.com> wrote:
> [skip]
>
>> for i=1,3 then begin
>
>> dummy = execute(plot,arr_'+string(i,format='(i1)')
>
>> endfor
>
> Is it just me that feels that such a code is quite ugly
> and obscure?
>
> I mean, if we start using "execute" every time we encounter
> some IDL coding difficulties, we may end up with programs
> that look like the following incomprehensible and marginally
> useful piece of code (that I am pretty sure the google goups
> post utilities will break up in all the wrong places).
>
> execute='(i=execute("'&execute=execute(execute+'"'+$
> '))--')&i$1i='print'&i1$i='scope_varname'&i2$i=' s'+$
> 'trtrim'&i$i='i'&i$i=i$i+'$i=('+i2$i+'('+i1$i+'(' +$
> i$i+')'+','+i$i+'+++1))[0]'&execute=execute(i$i)&i=$
> ' for '+i$i+' = '&execute=execute('i2$i='+i2$i+'('+$
> call_function(i2$i,execute) +',2)')&execute=i+i2$i+$
> ','+i2$i+i2$i+' do '+i$1i+','+i$i
> execute=execute(execute)
>
> Ciao,
> Paolo
>
> PS: I can't offer any excuse for posting this, other
> than it seems this group has become more boring
> in David's absence...
You're a sick man, Paolo. ;-)
-Jeremy.
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| Re: i don't see how to summarize it into an object name... :) [message #68107 is a reply to message #68090] |
Thu, 17 September 2009 12:32 |
pgrigis
Messages: 436
Registered: September 2007
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Senior Member |
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[skip]
> for i=1,3 then begin
>
> dummy = execute(plot,arr_'+string(i,format='(i1)')
>
> endfor
Is it just me that feels that such a code is quite ugly
and obscure?
I mean, if we start using "execute" every time we encounter
some IDL coding difficulties, we may end up with programs
that look like the following incomprehensible and marginally
useful piece of code (that I am pretty sure the google goups
post utilities will break up in all the wrong places).
execute='(i=execute("'&execute=execute(execute+'"'+$
'))--')&i$1i='print'&i1$i='scope_varname'&i2$i=' s'+$
'trtrim'&i$i='i'&i$i=i$i+'$i=('+i2$i+'('+i1$i+'(' +$
i$i+')'+','+i$i+'+++1))[0]'&execute=execute(i$i)&i=$
' for '+i$i+' = '&execute=execute('i2$i='+i2$i+'('+$
call_function(i2$i,execute) +',2)')&execute=i+i2$i+$
','+i2$i+i2$i+' do '+i$1i+','+i$i
execute=execute(execute)
Ciao,
Paolo
PS: I can't offer any excuse for posting this, other
than it seems this group has become more boring
in David's absence...
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| Re: i don't see how to summarize it into an object name... :) [message #68108 is a reply to message #68107] |
Thu, 17 September 2009 12:05 |
Andi Walther
Messages: 5
Registered: March 2009
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Junior Member |
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On Sep 17, 6:29 pm, pp <pp.pente...@gmail.com> wrote:
> 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
for i=1,3 then begin
dummy = execute(plot,arr_'+string(i,format='(i1)')
endfor
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| 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
Administrator |
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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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