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Re: "foreach" loops in IDL [message #64869 is a reply to message #64795]

Tue, 20 January 2009 13:11

JD Smith
Messages: 850
Registered: December 1999

Senior Member

On Jan 16, 3:43 pm, Vince Hradil <vincehra...@gmail.com> wrote:
> I would have to agree with Paolo here. The for-loop syntax is simple
> and clear. The @do @done really obfuscates the code.

That's because it's an unsupported add-on. If IDL included foreach at
the language level, which would be clearer:

for i=0,n_elements(x)-1 do begin
elem=x[i]
print, my_function(elem)
end

or

foreach elem in x
print, my_function(elem)
end

When treating a vector as a list, requiring an extra loop variable is
pure syntactic overhead. Not to mention that the loop variable could
overflow, could get changed in the body of the loop or, most commonly,
risks nested sub-loops accidentally re-using the same loop variable.
None of these happens with a foreach construct.

JD

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[Message index]

		Re: "foreach" loops in IDL By: R.Bauer on Mon, 19 January 2009 02:31
		Re: "foreach" loops in IDL By: rtk on Fri, 16 January 2009 13:07
		Re: "foreach" loops in IDL By: Vince Hradil on Fri, 16 January 2009 12:43
		Re: "foreach" loops in IDL By: pgrigis on Fri, 16 January 2009 12:34
		Re: "foreach" loops in IDL By: rtk on Fri, 16 January 2009 12:18
		Re: "foreach" loops in IDL By: pgrigis on Fri, 16 January 2009 11:37
		Re: "foreach" loops in IDL By: rtk on Fri, 16 January 2009 10:54
		Re: "foreach" loops in IDL By: JD Smith on Tue, 20 January 2009 13:11
		Re: "foreach" loops in IDL By: alaniwiusenet on Sat, 31 January 2009 04:20

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