comp.lang.idl-pvwave archive: archive » Re: simple array math question

Home » Public Forums » archive » Re: simple array math question

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

Re: simple array math question [message #33799 is a reply to message #33670]

Sat, 25 January 2003 01:12

Jeff Guerber
Messages: 41
Registered: July 2000

Member

On Mon, 20 Jan 2003, Marc Schellens wrote:

> If you index an array in IDL with another array,
> IDL always eats it, and sets the index to the bounds of the
> array.
>
> e.g:
> IDL> print,indgen(5)-1
> -1 0 1 2 3
> IDL> a=indgen(3)
> IDL> print,a[indgen(5)-1]
> 0 0 1 2 2
>
> so the result is:
> a[0], a[0], a[1], a[2], a[2]
>
> this works for all dimensions, so in you case
> b[*,[10,10,10,10],[10,10]]
>
> is the same as
>
> b[*,[0,0,0,0],[0,0]]
>
> because b is
> B INT = Array[3]
>
> which is in IDL the same as:
> Array[3,0,0,0,0,0,0,0]
>
> hope that helped,
> marc

That did indeed, thanks Marc! I think it was mostly the trailing
degenerate dimensions that I was missing. It's instructive too to play
around with this with a two-dimensional b:

IDL> b=[[1,2,3],[4,5,6]]
IDL> print,b[*,[0,0]]
1 2 3
1 2 3
IDL> print,b[*,[0,1,2],[-1,0,1,2]]
1 2 3
4 5 6
4 5 6

1 2 3
4 5 6
4 5 6

1 2 3
4 5 6
4 5 6

1 2 3
4 5 6
4 5 6
IDL>

Jeff Guerber

Report message to a moderator

[Message index]

		Re: simple array math question By: marc schellens[1] on Sun, 19 January 2003 22:55
		Re: simple array math question By: Jeff Guerber on Fri, 17 January 2003 20:21
		Re: simple array math question By: Heinz Stege on Fri, 17 January 2003 16:51
		Re: simple array math question By: Sean Raffuse on Fri, 17 January 2003 14:10
		Re: simple array math question By: JD Smith on Fri, 17 January 2003 13:46
		Re: simple array math question By: Craig Markwardt on Thu, 16 January 2003 19:47
		Re: simple array math question By: Heinz Stege on Thu, 16 January 2003 16:26
		Re: simple array math question By: Craig Markwardt on Thu, 16 January 2003 13:30
		Re: simple array math question By: Pepijn Kenter on Fri, 24 January 2003 04:43
		Re: simple array math question By: JD Smith on Thu, 23 January 2003 08:53
		Re: simple array math question By: Heinz Stege on Sun, 26 January 2003 11:25
		Re: simple array math question By: Jeff Guerber on Sat, 25 January 2003 01:12

Previous Topic:	MOUSE (WHEEL) BUTTON NON-STOP SCROLLING IN IDL 5.6
Next Topic:	Re: Windows XP graphics problem

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 18:04:28 PDT 2025

Total time taken to generate the page: 0.00522 seconds