| getting structure elements by tag name string [message #33497] |
Wed, 08 January 2003 03:03  |
![s[1] is currently offline](theme/default/images/xoffline.png.pagespeed.ic.XRkd1fkXye.png "s[1] is currently offline")
s[1]
Messages: 21
Registered: December 2002
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Junior Member |
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Hi all,
I try to use a structure as a bad substitute for a hash map (hashs or
associative lists or dictionaries or anything similar don't exist in
IDL, do they?)
Suppose I have a structure like this:
s = {a:7,b:9}
and I have a variable that contains a tag name:
tag = 'a'
Now I want to put the value of the structures element with name tag into a
new variable called value:
value = s.tag
This doesn't work of course, because tag is undefined for this structure.
But how can I get this the elements value?
I found a somewhat crude way:
res = execute('value =' + 's.' + tag)
That works, but it's really ugly. Is there a better way to do this?
And, is there a way to delete an element from a structure?
Thanks for all tips,
Sebastian
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| Re: getting structure elements by tag name string [message #33534 is a reply to message #33497] |
Thu, 09 January 2003 11:55  |
dscherba
Messages: 1
Registered: January 2003
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Junior Member |
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In article <3E1DAF62.487FB29F@hotmail.com>, Pavel A. Romashkin wrote:
> arrays? They do create indices, true, but still they serch them somehow,
> and that is fast. I'd say the speed is size-dependent, but it doesn't
> seem to be linearly proportional.
Different database systems use different methods, but all of them are
sub-linear in some sense (if they weren't, there would be little point
in indexing). Common methods are hash tables (essentially constant
lookup), and various search trees (balanced k-ary search trees have a
lookup time of O(log n)). In the real world(tm) things get a bit
messier, but that's the idea.
As for the original query, I have been known to use the EXECUTE()
function to get my structure elements by tag string.
Regards,
David
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