Re: Newbie - delete item from collection

Hi,

Thanks for that - it's good to know.  Do you have a reference for this as a
general behaviour, or is it just a compiler-specific optimisation?

Cheers,

			Geoff

> -----Original Message-----
> From: Discussion of advanced .NET topics. [mailto:ADVANCED-
> [email protected]] On Behalf Of Hewitt, Simon C. (Contractor)
> Sent: 18 November 2008 10:43
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] Newbie - delete item from collection
> 
> That's true for Arrays as the compiler 'knows' that .Length won't
> change
> during the enumeration.
> Everything else will have its Count re-evaluated during each loop.
> 
> Cheers
> Simon
> 
> -----Original Message-----
> From: Discussion of advanced .NET topics.
> [mailto:[email protected]] On Behalf Of Geoff Taylor
> Sent: 18 November 2008 10:20
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] Newbie - delete item from collection
> 
> I know it's a property.  Tsk. ;)
> 
> My confusion was around it being whether it was invoked in the loop at
> all.
> I was under the impression - I'm sure I read this somewhere back in the
> .NET 1.0 or beta days - that a for loop like:
> 
> for (int i = 0; i < list.Count; i++)
> {
>     ...
> }
> 
> Was created in the IL as:
> 
> int temp = list.Count;
> for (int i = 0; i < temp; i++)
> {
>     ...
> }
> 
> See what I mean now?
> 
> I can't find any reference to this behaviour though, and I've just read
> the relevant parts of the C# Language Specification and it's not there.
> I even wrote it a simple program in Snippet Compiler to check.  So it
> looks like my understanding was hogswash.  Sorry about that.
> 
> Apologies for introducing confusion.  Now, any idea where I got that
> notion?
> 
> Cheers,
> 
> 			Geoff
> 
> > -----Original Message-----
> > From: Discussion of advanced .NET topics. [mailto:ADVANCED-
> > [email protected]] On Behalf Of Eddie Lascu
> > Sent: 17 November 2008 22:23
> > To: [email protected]
> > Subject: Re: [ADVANCED-DOTNET] Newbie - delete item from collection
> >
> > Count is a property that returns the actual number of elements
> > contained in the ArrayList so has to be reevaluated every time is
> > invoked.
> >
> > -----Original Message-----
> > From: Discussion of advanced .NET topics.
> > [mailto:[email protected]] On Behalf Of Geoff
> > Taylor
> > Sent: Monday, November 17, 2008 5:06 PM
> > To: [email protected]
> > Subject: Re: [ADVANCED-DOTNET] Newbie - delete item from collection
> >
> > Really? I thought that was cached before the first iteration of the
> > loop and not re-evaluated. Does it really evaluated Count each time
> > through the loop?
> >
> >      Geoff
> >
> > On 17 Nov 2008, at 21:04, Chris Anderson <[email protected]> wrote:
> >
> > >> (I'd also have expected it to throw an exception towards the end,
> > >> because there are no longer _someList.Count items in the list.)
> > >
> > > Yes there are ;-)
> > > _someList.Count will be decrementing as you remove items
> > >
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