comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Re: Array slices

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

Re: Array slices [message #47247]

Thu, 02 February 2006 08:58

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Richard Edgar writes:

> I'm having trouble with slices of 3D arrays in IDL, and I suspect that
> it's something I don't understand about the way IDL interprets things.
> My problem can be summed up as follows:
>
> IDL> arr=DINDGEN(3,3,3)
> IDL> help,arr
> ARR DOUBLE = Array[3, 3, 3]
> IDL> help,arr[*,*,1]
> <Expression> DOUBLE = Array[3, 3]
> IDL> help,arr[*,1,*]
> <Expression> DOUBLE = Array[3, 1, 3]
> IDL> help,arr[1,*,*]
> <Expression> DOUBLE = Array[1, 3, 3]
>
> My questions are:
> a) Why don't all three slices return a [3,3] array?
> b) How do I eliminate the 'useless' dimension?
>
> I typically have routines which want a 2D array, which I only get from
> the first of these. They (naturally) choke when given a 3D array, one of
> whose dimensions is unity.

One man's "useless" dimension is another man's "essential"
dimension, as you will learn if you follow this newsgroup
for any length of time. The lamentations over the "missing"
dimension are legendary.

But, if it is really useless to you, then REFORM it away:

IDL> Help, Reform(array[3,1,3], 3, 3)
<Expression> DOUBLE = Array[3, 3]

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/

Report message to a moderator

[Message index]

		Re: Array slices By: David Fanning on Thu, 02 February 2006 08:58
		Re: Array slices By: Anne[1] on Thu, 02 February 2006 08:53
		Re: Array slices By: Richard Edgar on Thu, 02 February 2006 09:52

Previous Topic:	display line numbers in idlde?
Next Topic:	Re: Speeding up multiple file reading

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 11:25:12 PDT 2025

Total time taken to generate the page: 0.79730 seconds