You are correct it was probably a bad choice of wording to use "retreive",
iteration is what is actually occuring. When it comes down to it, I think
I just confused myself on the issue, I was thinking to much on how foreach
iterates over a hash. I should have just ran a test before hand to
check...my bad. I was just having a brain fart.
thanks for you're comments,
Jeffl
EOF
On 2001.09.07 12:23 Bob Showalter wrote:
> > -----Original Message-----
> > From: Jeffl [mailto:[EMAIL PROTECTED]]
> > Sent: Friday, September 07, 2001 11:47 AM
> > To: Bob Showalter
> > Cc: 'beginners @ perl . org'
> > Subject: RE: foreach and the ordering of array's
> >
> >
> > when you run a foreach on a hash you have no idea what order
> > you will get
> > the keys unless
> > you sort it, then you can only get it in the order defined by
> > sort. If you
> > use Tie::IxHash
> > on a hash you can print out the has in the order it was constructed.
> >
> > Basically, I couldn't remeber what the Camel said about foreach and
> > accessing an array.
> > I went back and found this, which ties into what I had
> > thought...(quote
> > from the camel v.3
> > pg.118) "There is no way with foreach to tell where you are
> > in a list. You
> > may compare adjacent elements by remembering the perevious one in a
> > variable, but sometimes you just have to break down and write
> > a three-part
> > for loop with subscripts."
> >
> > So basically, what I get out of this, is that you don't know
> > the order that
> > foreach will retrieve the elements of the '@'. Now I could be mistaken
> > here, and am not seeing the forest for the trees, and I
> > should have just
> > run a test to find out for myself.....I'm off to go build an
> > @ and find out
> > the order it parses through in a foreach, which I should have
> > done in the
> > first place......doh.....It was late......cut me some slack.
>
> Some confusion in the terminology here.
>
> for/foreach does not "retrieve" anything. It iterates over a list.
> It will iterate over that list in the exact order the list elements
> are supplied to for/foreach. Guaranteed.
>
> One way to supply a list to for/foreach is to use the keys() function
> to retrieve a list of the keys in a hash. keys() does not return the
> key values in any particular order, due to the internal representation
> of a hash.
>
> But you want to supply an array to for/foreach. In that case, the
> elements of the array are supplied in the array index sequence, which is
> what you are looking for. This holds for any list context where an array
> is used, not just for/foreach (e.g. print(), join(), map(), etc.)
>
> (Inside the body of a for/foreach loop, you cannot determine the
> subscript
> of the current array element you are processing. This is obvious, because
> there is nothing that says the list supplied to for/foreach came from a
> single array in the first place. But that doesn't mean that the loop does
> not interate over the list in a guaranteed sequence.)
>
> I'm sure others can explain this better than I can. But you are on the
> right track to construct a test to confirm the behavior.
>
> --
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
>
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
