| Re: Merits of different ways of 'extending' arrays [message #85805 is a reply to message #85798] |
Tue, 10 September 2013 13:08   |
suicidaleggroll
Messages: 14
Registered: September 2013
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Junior Member |
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On Monday, September 9, 2013 4:41:10 PM UTC-6, suicida...@gmail.com wrote:
> Another option is to set up a pointer array nfiles long before the loop, inside the loop load the file and find the valid points, then put that array into that file's pointer, while incrementing a counter to keep track of the total number of points. When you're done, you have all of your data saved in pointers (one per file), and a count of the total number of valid points. Then you allocate your array, loop back through the elements of the pointer array, and fill the array as necessary. Something like:
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> f = file_search(path, count=nfiles)
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> ptrs = ptrarr(nfiles)
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> num = 0l
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> for i=0l,nfiles-1 do begin
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> ;; load contents of file
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> is_valid = where(stuff, n_valid)
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> if n_valid gt 0 then begin
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> num += n_valid
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> ptrs[i] = ptr_new(f.var_1[is_valid])
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> endif
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> endfor
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>
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> data = fltarr(num)
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> idx = 0l
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> for i=0l,nfiles-1 do begin
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> if ptr_valid(ptrs[i]) then begin
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> num = n_elements(*ptrs[i])
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> data[idx:idx+num-1] = *ptrs[i]
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> ptr_free, ptrs[i]
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> endif
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> endfor
Wish I could edit my post...
There should be an "idx += num" next to the ptr_free at the end of the second loop.
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