It's not especially important, but I always like to know the best way of doing
things for when I encounter a case where performance becomes a factor... say I
have a string array and I want to get a distinct list, that is, get a list
without duplicates. In SQL this is easy because it's done for you. In code, what
would be the best practice? Array.Sort(stringarray) followed by n comparisons
collecting on the changes? Or perhaps adding each string as a key to a
collection or hashtable and just letting duplicates refusal do the work? I have
always wondered, are there circumstances when catching errors in quantity like
this degrade performance? Is it common, avoided?

Bob

On 2004-02-02, Bob <(E-Mail Removed)> wrote:
> It's not especially important, but I always like to know the best way of doing
> things for when I encounter a case where performance becomes a factor... say I
> have a string array and I want to get a distinct list, that is, get a list
> without duplicates. In SQL this is easy because it's done for you. In code, what
> would be the best practice? Array.Sort(stringarray) followed by n comparisons
> collecting on the changes? Or perhaps adding each string as a key to a
> collection or hashtable and just letting duplicates refusal do the work? I have
> always wondered, are there circumstances when catching errors in quantity like
> this degrade performance? Is it common, avoided?
>
> Bob

Catching exceptions is always expensive and should be avoided where
possible. Personally, I would use the hashtable approach, but I would
probably check if it existed first using the hashtable contains
method... The check would probably be less expensive then catching an
exception in terms of performance.

--
Tom Shelton [MVP]
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Well, you know, no matter where you go, there you are.
-- Buckaroo Banzai

Hi Bob,

I think just as you said,
Array.sort
Extra Arraylist
Loop 1 time through the sorted array from 0 to array.length
Add the first from the arry to the arraylist and every time the item is
another than the previous
Would go very fast I think.

For me are exceptions only for if you cannot manage the exception, let say a
file which is incomplete readed from disk.

And for no other things, have you seen how long it takes when there is an
exception in your debugger?

I hope this helps,

Cor

> It's not especially important, but I always like to know the best way of
doing
> things for when I encounter a case where performance becomes a factor...
say I
> have a string array and I want to get a distinct list, that is, get a list
> without duplicates. In SQL this is easy because it's done for you. In
code, what
> would be the best practice? Array.Sort(stringarray) followed by n
comparisons
> collecting on the changes? Or perhaps adding each string as a key to a
> collection or hashtable and just letting duplicates refusal do the work? I
have
> always wondered, are there circumstances when catching errors in quantity
like
> this degrade performance? Is it common, avoided?
>
> Bob
>

I sort of knew I shouldn't be lazy and let exception handling do the work, but I
wasn't sure. Thanks for the answers.

Bob