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Re: Array indexing problem [message #37853 is a reply to message #37852]

Thu, 29 January 2004 09:03

roberson_1
Messages: 10
Registered: November 2003

Junior Member

Thank you for responding so quickly. Compile_opt STRICTARRSUBS works
for IDL 6.0 but I have to use 5.1. Is there a way to add in a compile
function, or some else that will look for this error in the original
code? I don't want to add an error handler, which David suggested.
The original code can not be altered.

Roy

"Liam Gumley" <pip_book@mailinator.com> wrote in message news:<bv9c35$lqf$1@news.doit.wisc.edu>...
> "Roy" <roberson_1@yahoo.com> wrote in message
> news:c0a9aee5.0401281200.400888f1@posting.google.com...
>> Is there any existing code that will catch the below IDL simple
>> example? Input a and b must be an array.
>>
>> Input is an array:
>> IDL> b=[4]
>> IDL> a=[0,1,2]
>> IDL> print,a[b]
>> 2
>> This should give me an error.
>
> This is how array subscripting works in IDL, when the subscript is an array.
> To quote the IDL Manual "Building IDL Applications", Chapter 5, "Using
> Arrays as Subscripts":
>
> "If an element of the subscript array is less than or equal to zero, the
> first element of the subscripted variable is selected. If an element of the
> subscript is greater than or equal to the last subscript in the subscripted
> variable (N, above), the last element is selected."
>
> If the subscript variable has just one elements, then you can do this
> instead
>
> IDL> print, a[b[0]]
> % Attempt to subscript A with <LONG ( 4)> is out of range.
> % Execution halted at: $MAIN$
>
> since b[0] is a scalar. You can do this even if b is a scalar.
>
> Cheers,
> Liam.
> Practical IDL Programming
> http://www.gumley.com/

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[Message index]

		Re: Array indexing problem By: kashyap on Thu, 29 January 2004 15:21
		Re: Array indexing problem By: David Fanning on Thu, 29 January 2004 09:58
		Re: Array indexing problem By: Liam Gumley on Thu, 29 January 2004 09:43
		Re: Array indexing problem By: roberson_1 on Thu, 29 January 2004 09:03
		Re: Array indexing problem By: hunter on Wed, 28 January 2004 13:43
		Re: Array indexing problem By: Mark Hadfield on Wed, 28 January 2004 16:55
		Re: Array indexing problem By: David Fanning on Wed, 28 January 2004 14:40
		Re: Array indexing problem By: Paul Van Delst[1] on Wed, 28 January 2004 14:28
		Re: Array indexing problem By: Michael Wallace on Wed, 28 January 2004 14:23
		Re: Array indexing problem By: Liam Gumley on Wed, 28 January 2004 14:11
		Re: Array indexing problem By: David Fanning on Wed, 28 January 2004 13:34

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