Thanks Mike and Wizzud.
Question:
What I wanted to use this for was my cache and to "truncate" old
data. I see that using a real array will allow me to use the
inherited .length property to set a new size and it will do
truncation. But since I am using an associated array, the length
property is no longer usable.
So if I use the for loop with delete, will I be pulling the "rug from
under its feet?"
Typically, in code designs like this, you would do a reverse traversal
to delete the last entries first so you can keep with the internal
loop counters and/or references.
In other words, is this "safe?"
function pruneCache(amt) {
var n = 0;
for (var i in cache) {
if (amt > 0) {
amt--;
delete cache[i];
return;
}
n++;
}
cache.length = n;
}
If not, then in lieu of a reverse loop syntax, I would probably need
to copy the cache first? I have not checked but if returning false
stops the traveral that would be more efficient.
I could recode all this into a pure indexed array and then use
the .length, but then I would need a fast lookup method or 2nd matrix
to map the associated name with the array index.
Thanks
--
HLS
On Oct 11, 4:26 am, "Michael Geary" <[EMAIL PROTECTED]> wrote:
> > From: Pops
>
> > Is this the only way to iterate through an object?
>
> > for ( x in myObject) {
> > }
>
> Ultimately, yes. You can use something like $.each() on an object, but it
> just runs that same for loop internally - see the source code for $.each().
>
> > and how can you remove an field in an object?
>
> > For example:
>
> > var obj = {
> > x1: 1123,
> > x2: 212,
> > x3: 123131
> > };
>
> > I want to remove obj.x2 the obj object to end up with:
>
> > { x1: 1123, x3: 123131}
>
> delete obj.x2;
>
> or
>
> delete obj['x2'];
>
> Note that it is not an error if the property doesn't exist, so you don't
> have to "protect" the delete with code like this:
>
> if( 'x2' in obj ) delete obj.x2; // unnecessary precaution
>
> -Mike
