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Re: Specification for a new array slicing function [message #15564 is a reply to message #15437]

Thu, 20 May 1999 00:00

Martin Schultz
Messages: 515
Registered: August 1997

Senior Member

Liam Gumley wrote:
>

> I agree that START, STRIDE, COUNT are somewhat wordy. However I'd like
> to be able to specify them in any combination, e.g.
> I'm not sure I know a clean way to allow these combinations, other than
> using optional keywords.

well, if you set the ones you don't need to -1 (as this was suggested to
specify "all"). But at least for STRIDE, -1 should be possible as such
(see my other post).

> START only, or ARREX(array,START)
> STRIDE only, or ARREX(array,-1,-1,STRIDE)
> COUNT only, or ARREX(array,0,COUNT-1) ; you need a start to count !
> START and STRIDE, or ARREX(array,START,-1,STRIDE)
> START and COUNT, or ARREX(array,START,START+COUNT)
> STRIDE and COUNT, or ARREX(array,0,COUNT-1,STRIDE)
> START and STRIDE and COUNT. ARREX(array,START,START+COUNT,STRIDE)

Note that I used START,END,STRIDE as in F90.

Also: while START,END,STRIDE can be multi-dimensional, they must have
the same dimensions - -1 being an exception, e.g.
array=fltarr(10,10,10)
start=[0,0,5]
stride=[2,2,1]
help,arrex(array,start,-1,stride) should yield ARRAY[5,5,5]

Also, perhaps, an undefined parameter should also be interpreted as
"ALL" (and then be returned as -1), i.e. in the above example
arrex(array,start,theend,stride) should yield the same result
although THEEND wasn't defined

A boolean /REFORM keyword would be a nice feature.

Martin.

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Martin Schultz, DEAS, Harvard University, 29 Oxford St., Pierce 109,
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[Message index]

		Specification for a new array slicing function By: Liam Gumley on Wed, 19 May 1999 00:00
		Re: Specification for a new array slicing function By: bowman on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: Martin Schultz on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: Jack Saba on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: Martin Schultz on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: Liam Gumley on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: steinhh on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: Struan Gray on Thu, 20 May 1999 00:00
		Re: Specification for a new array slicing function By: Martin Schultz on Thu, 20 May 1999 00:00

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