| Re: sorting column arrays [message #49154] |
Fri, 30 June 2006 09:15 |
cgguido
Messages: 195
Registered: August 2005
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Senior Member |
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> The last line makes the sort in one go, since SORT doesn't guarantee
> anything about the order of identical elements. You might have to
> adjust the coefficients if your data has a wider range than the sample
> you show.
sort does indeed tend to jumble things up a little, but bsort does the
job right:
http://www.dfanning.com/tips/sort.html.
also, something like this should work....
IDL> d = $
IDL> [[4, 7, 0, 1], $
IDL> [3, 6, 2, 9],$
IDL> [2, 2, 0, 2],$
IDL> [42, 4, 2, 7],$
IDL> [256, 3, 0, 2],$
IDL> [34, 2, 1, 5]]
IDL>
IDL> s1 = bsort(d[1, *])
IDL> s2 = bsort(d[3, s1])
IDL> s3 = bsort(d[2, s1[s2]])
IDL> sd = d[*, s1[s2[s3]]]
IDL>
IDL> print, d, 'sorted by columns 2>3>1', sd
4 7 0 1
3 6 2 9
2 2 0 2
42 4 2 7
256 3 0 2
34 2 1 5
sorted by columns 2>3>1
4 7 0 1
2 2 0 2
256 3 0 2
34 2 1 5
42 4 2 7
3 6 2 9
Gianguido
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| Re: sorting column arrays [message #49158 is a reply to message #49154] |
Fri, 30 June 2006 05:30  |
greg michael
Messages: 163
Registered: January 2006
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Senior Member |
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How about this (no loop):
v=lonarr(4,n_elements(array))
reads,strmid(array,4),v
print,v[*,sort(v[1,*]+v[2,*]/10.+v[0,*]/100.)]
The last line makes the sort in one go, since SORT doesn't guarantee
anything about the order of identical elements. You might have to
adjust the coefficients if your data has a wider range than the sample
you show.
regards,
Greg
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