comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Sort

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Sort [message #10243 is a reply to message #10241]

Wed, 05 November 1997 00:00

savoie
Messages: 68
Registered: September 1996

Member

Neil Winrow <ncw@dl.ac.uk> writes:

> Can anybody please offer their help!

> I have three sets of data, X, Y, Z. I read these sets of data into one
> big array. I would like to sort one of the sets of data within the big
> array, lets say sort the Z data. Is it then possible for the
> corresponding values in the X and Y to also sort to the correct values.
> Hope someone can understand, and offer me a solution.

Neil,

I think you're looking for something like this?

IDL> x = indgen(10)
IDL> y = indgen(10) * 2
IDL> z = randomu(seed,10) *10
IDL> print, x
0 1 2 3 4 5 6 7 8
9
IDL> print, y
0 2 4 6 8 10 12 14 16
18
IDL> print, z
9.42273 7.87034 6.82765 2.36464 2.45571 3.17787
0.410162 3.58485 0.540125 7.87818

IDL> sortindex = sort(z)
IDL> print, sortindex
6 8 3 4 5 7
2 1 9 0
IDL> print, z(sortindex)
0.410162 0.540125 2.36464 2.45571 3.17787 3.58485
6.82765 7.87034 7.87818 9.42273
IDL> print, x(sortindex)
6 8 3 4 5 7 2 1 9
0
IDL> print, y(sortindex)
12 16 6 8 10 14 4 2 18
0

The key is that the IDL sort routine returns an array of indices into
the array to be sorted. So that by using the array subscripted by the
indices, you get the sorted array.

Hope this helps.
matthew

--
Matthew H. Savoie Systems Technology Associates
Systems Analyst Supporting NOAA Profiler Network
ph. 303.497.6642 Demonstration Division/FSL/ERL
mailto: savoie@fsl.noaa.gov <URL:http://www-dd.fsl.noaa.gov/online.html>

Report message to a moderator

[Message index]

		Sort By: Neil Winrow on Wed, 05 November 1997 00:00
		Re: Sort By: Ian Sprod on Wed, 05 November 1997 00:00
		Re: Sort By: savoie on Wed, 05 November 1997 00:00
		Re: Sort By: Martin Schultz on Wed, 05 November 1997 00:00
		Re: Sort By: David Foster on Fri, 07 November 1997 00:00
		Re: Sort By: pit on Thu, 06 November 1997 00:00

Previous Topic:	IDL style sheet for a2ps
Next Topic:	A rant: features vs. programming features

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 15:46:35 PDT 2025

Total time taken to generate the page: 1.84195 seconds