comp.lang.idl-pvwave archive: archive » Re: array concatenation in 2-D

Home » Public Forums » archive » Re: array concatenation in 2-D

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

Re: array concatenation in 2-D [message #59754 is a reply to message #59623]

Tue, 08 April 2008 18:19

elwood
Messages: 23
Registered: February 2007

Junior Member

On Apr 4, 2:31 pm, Jean H <jghas...@DELTHIS.ucalgary.ANDTHIS.ca>
wrote:
> elwood wrote:
>> I have a loop which calculates two variables x[i] and y[i]
>
>> At each iteration of the loop I calculate
>> x and y
>> And I'd like to concatenate x and y into a 2 column, unknown numbers
>> of rows
>> output array.
>> I'd like to dynamically grow the output array at each interation.
>
>> For example:
>> x=1 y=5 on first iteration
>> x=2, y=6 on 2nd iteration
>> I want an output array that looks like the below:
>
>> 1 5
>> 2 6
>
>> How do i achieve this without knowing the array size??
>
>> Tx!
>> -Elisha
>
> Elisha,
> You can concatenate the arrays, as you suggest:
>
> a = [[1,2],[3,4]]
> a = [[a],[5,6]]
> help,a
> ==>A INT = Array[2, 3]
>
> However, if you have many elements, this can be very resources
> consuming. Another option is to create a "big" 2*n array, to
> progressively fill it, to keep a counter on the number of entries, and
> finally to cut what you haven't used.... and similarly, if your array is
> not big enough, add a large number of rows and keep filling them (use
> the same concatenation method as above)
>
> Jean

Alas, this is a form of concatenation, but it does not produce
the required results.
I need to concatenate by COLUMN, not row.
If I code the concatenation you show, it produces:
column 1:
1 2
3 4
5 6

Whereas I need it to paste the columns together such that I
get
1 3 5
2 4 6

To be specific, each iteration of the loop
I calculate new values of x and y
I want to do the following, but using concatenation
outputarry[0,0]=x1
outputarry[1,0]=y1

next iteration
outputarry[0,1]=x2
outputarry[1,1]=y2

to get a final array where x values are in column 0
y values are in column 1

Report message to a moderator

[Message index]

		Re: array concatenation in 2-D By: ben.bighair on Fri, 04 April 2008 14:25
		Re: array concatenation in 2-D By: Jean H. on Fri, 04 April 2008 12:31
		Re: array concatenation in 2-D By: David Fanning on Fri, 04 April 2008 12:40
		Re: array concatenation in 2-D By: R.G. Stockwell on Fri, 04 April 2008 12:27
		Re: array concatenation in 2-D By: David Fanning on Fri, 04 April 2008 11:57
		Re: array concatenation in 2-D By: elwood on Tue, 08 April 2008 18:19

Previous Topic:	Re: No removal of "NaN" while plotting on both PLOT and iPLOT
Next Topic:	Re: Tilde with IDL

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sat Oct 11 04:02:23 PDT 2025

Total time taken to generate the page: 0.40172 seconds