| Workaround for lack of foo.([]) capability with structures? [message #74591] |
Mon, 24 January 2011 20:18 |
Matt Francis
Messages: 94
Registered: May 2010
|
Member |
|
|
I have a data structure with many tags, and an array of these
structures holding a bunch of data.
Many of the tags will often not be present or relevant in some
particular context, and so will be just zeros for the whole array. I
want to be able to selectively write out to file just those tage that
contain usefull data.
I have a line like this for the case that I want to write out all the
tags:
for i=0l,n_elements(foo)-1 do $
printf,lunw,foo[i], format=FMT
If however I want to write out not all of the tags, I'm not sure how
to do this? I can create an appropriate FMT string for the subset of
tags, and could do something like:
for i=0l,n_elements(foo)-1 do $
printf,lunw,foo[i].tag1,foo[i].tag2, format=FMT
where I list just those tags I want written out. This hard codes what
tags to write though. Since there are many possible combinations of
which ones I want written out, I'd need dozens of IF/THEN lines like
if (want tags 1 and 2) then begin
for i=0l,n_elements(foo)-1 do $
printf,lunw,foo[i].tag1,foo[i].tag2, format=FMT'
endif else if (want tags 1 and 3 ) then begin
for i=0l,n_elements(foo)-1 do $
printf,lunw,foo[i].tag1,foo[i].tag3, format=FMT'
endelse
This is clearly not the solution. I can easily create an array
indicating the tags I want written out and would love to be able to
simply use the command:
for i=0l,n_elements(foo)-1 do $
printf,lunw,foo[i].(indx), format=FMT
but IDL (at least my V7.1) does not allow this kind of indexing. Tags
can only be directly indexed, not via arrays of indices.
I could do something like
for i=0l,n_elements(foo)-1 do begin
for j=0,ntags-1 do begin
printf,lunw,foo[i].(indx[j])
endfor
endfor
however this creates a newline for each printf statement, and I need
all the data for each array element on one line.
Any ideas?
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
