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Re: Filling an array [message #23293 is a reply to message #23284]

Wed, 17 January 2001 17:18

davidf
Messages: 2866
Registered: September 1996

Senior Member

Pavel A. Romashkin (pavel.romashkin@noaa.gov) writes:

> If I have
>
> a = findgen(10)
> b = fix(100* randomu(10, 10))
> ; N_elements(a) is equal to n_elements(b)
> c = findgen(total(b))
>
> how can I fill C with values from A using B as a running index, so that
>
> c[0 : b[0]-1] = a[0]
> c[b[0] : b[0]+b[1]-1] = a[1]
>
> etc, without looping through "n_elements(b)-1" iterations?
> I have a fast solution with a loop and indexing using total(/cumulative)
> and a very slow one with loop and replicate, but I can't come up with a
> loop-free one.

Totally impossible. :-(

Cheers,

P.S. Let's just say that usually gets the juices going
on the usual suspects, and I figured you could use the
help. :-)

--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		Re: Filling an array By: Pavel A. Romashkin on Thu, 18 January 2001 16:43
		Re: Filling an array By: Craig Markwardt on Thu, 18 January 2001 13:40
		Re: Filling an array By: davidf on Thu, 18 January 2001 12:52
		Re: Filling an array By: John-David T. Smith on Thu, 18 January 2001 12:28
		Re: Filling an array By: Pavel A. Romashkin on Thu, 18 January 2001 09:03
		Re: Filling an array By: Craig Markwardt on Wed, 17 January 2001 21:37
		Re: Filling an array By: davidf on Wed, 17 January 2001 17:18

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