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Re: negative array index in IDL8 [message #86475 is a reply to message #86382]

Tue, 12 November 2013 12:21

chuxiangning
Messages: 17
Registered: September 2012

Junior Member

On Saturday, November 2, 2013 7:43:28 AM UTC-7, David Fanning wrote:
Thanks for your response. Considering the huge amount of libraries out there, I have to adhere to IDL 7 after all efforts.

> chu xiangning writes:
>
>
>
>> On Friday, November 1, 2013 3:18:24 PM UTC-7, wlandsman wrote:
>
>>> Not the answer to the question you are asking, but if you are only using IDL8 or above, you could mindlessly add /NULL to all your WHERE() statements ( or write a simple script to do this). This is likely easier than adding tests for negative indices. --Wayne
>
>>
>
>> Thanks for the solution. It is ok for new codes. It is all the codes and packages already written that might return wrong results with IDL 8. And we can afford to change them. One simple solution is 'don't buy IDL 8'.
>
>
>
> Yes, this will work for awhile, but not for too much longer. Sooner or
>
> later someone you know who uses your software will have IDL 8 and then
>
> the problem will reappear. :-)
>
>
>
> This was a controversial decision when it was first contemplated. But,
>
> put yourself in the place of the IDL developers. You want to make your
>
> software fresh and relevant, and you want it to have some of the same
>
> kind of features newer programming languages have. Here is a change you
>
> can make that will make a great many people pleased and it can be done
>
> without harming backwards compatibility for most of the programmers you
>
> know personally (i.e., those professional programmers that understand
>
> how the Where function works and don't rely on IDL errors to do their
>
> programming for them).
>
>
>
> What would you have done? It's a pretty close call for me. But, I
>
> understand why you might decide not to let past bad programming
>
> practices interfere with your need to improve the language. I don't hold
>
> this decision against the folks at ExelisVis. And, in the positive
>
> column, giving people incentive to write programs correctly might
>
> actually pay off in the long run. ;-)
>
>
>
> I say use a Grep program to search for instances of Where in your IDL
>
> program library and spend a half a day fixing the damn things. It will
>
> cost you half a day now, but you will be glad you did it for a long,
>
> long time.
>
>
>
> Cheers,
>
>
>
> David
>
>
>
> --
>
> David Fanning, Ph.D.
>
> Fanning Software Consulting, Inc.
>
> Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
>
> Sepore ma de ni thue. ("Perhaps thou speakest truth.")

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[Message index]

		negative array index in IDL8 By: chuxiangning on Fri, 01 November 2013 10:38
		Re: negative array index in IDL8 By: suicidaleggroll on Fri, 01 November 2013 11:55
		Re: negative array index in IDL8 By: David Fanning on Fri, 01 November 2013 12:03
		Re: negative array index in IDL8 By: chuxiangning on Fri, 01 November 2013 13:05
		Re: negative array index in IDL8 By: David Fanning on Fri, 01 November 2013 13:31
		Re: negative array index in IDL8 By: wlandsman on Fri, 01 November 2013 15:18
		Re: negative array index in IDL8 By: chuxiangning on Fri, 01 November 2013 19:38
		Re: negative array index in IDL8 By: wlandsman on Sat, 02 November 2013 06:42
		Re: negative array index in IDL8 By: David Fanning on Sat, 02 November 2013 07:43
		Re: negative array index in IDL8 By: chuxiangning on Tue, 12 November 2013 12:21

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