I''m trying to remove all objects and object references from myArray.
But code below brakes before last iteration - myArray contains still
one element.
myArray.each( function(content, index) {
delete content; myArray.splice(index,1);
});
Is there any solution, how I can decrease this array inside #each ?
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Hi,
That''s because you''re modifying the array''s contents
within the
iterator, which is pretty much a no-no. (You can modify the things
each array element points to, but changing the actual content of the
array is problematic.) Just glancing at the #_each method in Array
(which is what #each calls) in prototype.js would reveal why:
_each: function(iterator) {
for (var i = 0, length = this.length; i < length; i++)
iterator(this[i]);
},
So #each probably isn''t the best way to approach this. Even if it
were, re-splicing the array every time is also going to be seriously
inefficient.
The good news is that all you need to do is set the array''s length to
0. You can do that directly, or call the tempting Prototype
Array#clear method:
http://www.prototypejs.org/api/array/clear
Setting the array''s length automatically deletes any properties that
the new length would leave out; see the ECMA spec, Section 15.4:
http://www.ecma-international.org/publications/standards/Ecma-262.htm
Hope this helps,
--
T.J. Crowder
tj / crowder software / com
On Jun 23, 4:13 am, mocambo <moca...-S7FoVGKkKTI@public.gmane.org>
wrote:> I''m trying to remove all objects and object references from
myArray.
> But code below brakes before last iteration - myArray contains still
> one element.
>
> myArray.each( function(content, index) {
> delete content; myArray.splice(index,1);
>
> });
>
> Is there any solution, how I can decrease this array inside #each ?
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Thanks for your exhaustive explanation !
I''ve solved this issue following:
var _myArray = myArray.clone();
_myArray.each( function(content, index) {
delete content; myArray.splice(index,1);
});
delete _myArray;
On Jun 23, 10:39 am, "T.J. Crowder"
<t...-MUGVhKWuB3Yd9SLi6J12IkEOCMrvLtNR@public.gmane.org>
wrote:> Hi,
>
> That''s because you''re modifying the array''s
contents within the
> iterator, which is pretty much a no-no. (You can modify the things
> each array element points to, but changing the actual content of the
> array is problematic.) Just glancing at the #_each method in Array
> (which is what #each calls) in prototype.js would reveal why:
>
> _each: function(iterator) {
> for (var i = 0, length = this.length; i < length; i++)
> iterator(this[i]);
> },
>
> So #each probably isn''t the best way to approach this. Even if it
> were, re-splicing the array every time is also going to be seriously
> inefficient.
>
> The good news is that all you need to do is set the array''s length
to
> 0. You can do that directly, or call the tempting Prototype
> Array#clear method:http://www.prototypejs.org/api/array/clear
>
> Setting the array''s length automatically deletes any properties
that
> the new length would leave out; see the ECMA spec, Section
15.4:http://www.ecma-international.org/publications/standards/Ecma-262.htm
>
> Hope this helps,
> --
> T.J. Crowder
> tj / crowder software / com
>
> On Jun 23, 4:13 am, mocambo <moca...-S7FoVGKkKTI@public.gmane.org>
wrote:
>
> > I''m trying to remove all objects and object references from
myArray.
> > But code below brakes before last iteration - myArray contains still
> > one element.
>
> > myArray.each( function(content, index) {
> > delete content; myArray.splice(index,1);
>
> > });
>
> > Is there any solution, how I can decrease this array inside #each ?
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> I''ve solved this issue following:But....why?! Just set the length to zero. No need for all of the cloning and splicing! -- T.J. Crowder tj / crowder software / com On Jun 23, 8:43 pm, mocambo <moca...-S7FoVGKkKTI@public.gmane.org> wrote:> Thanks for your exhaustive explanation ! > > I''ve solved this issue following: > > var _myArray = myArray.clone(); > > _myArray.each( function(content, index) { > delete content; myArray.splice(index,1); > > }); > > delete _myArray; > > On Jun 23, 10:39 am, "T.J. Crowder" <t...-MUGVhKWuB3Yd9SLi6J12IkEOCMrvLtNR@public.gmane.org> wrote: > > > Hi, > > > That''s because you''re modifying the array''s contents within the > > iterator, which is pretty much a no-no. (You can modify the things > > each array element points to, but changing the actual content of the > > array is problematic.) Just glancing at the #_each method in Array > > (which is what #each calls) in prototype.js would reveal why: > > > _each: function(iterator) { > > for (var i = 0, length = this.length; i < length; i++) > > iterator(this[i]); > > }, > > > So #each probably isn''t the best way to approach this. Even if it > > were, re-splicing the array every time is also going to be seriously > > inefficient. > > > The good news is that all you need to do is set the array''s length to > > 0. You can do that directly, or call the tempting Prototype > > Array#clear method:http://www.prototypejs.org/api/array/clear > > > Setting the array''s length automatically deletes any properties that > > the new length would leave out; see the ECMA spec, Section 15.4:http://www.ecma-international.org/publications/standards/Ecma-262.htm > > > Hope this helps, > > -- > > T.J. Crowder > > tj / crowder software / com > > > On Jun 23, 4:13 am, mocambo <moca...-S7FoVGKkKTI@public.gmane.org> wrote: > > > > I''m trying to remove all objects and object references from myArray. > > > But code below brakes before last iteration - myArray contains still > > > one element. > > > > myArray.each( function(content, index) { > > > delete content; myArray.splice(index,1); > > > > }); > > > > Is there any solution, how I can decrease this array inside #each ? > >--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Spinoffs" group. To post to this group, send email to rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-spinoffs?hl=en -~----------~----~----~----~------~----~------~--~---
You could always do it recursively. ;-) If only JavaScript had tail
recursion!
function eraseArray(a) {
delete a[0];
if (a.length > 0)
eraseArray(a.slice(1));
}
-Fred
On Mon, Jun 23, 2008 at 4:02 PM, T.J. Crowder
<tj-MUGVhKWuB3Yd9SLi6J12IkEOCMrvLtNR@public.gmane.org>
wrote:
>
> > I''ve solved this issue following:
>
> But....why?! Just set the length to zero. No need for all of the
> cloning and splicing!
--
Science answers questions; philosophy questions answers.
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Sorry for confusion !
My sample here was simplified. Actually I have much more logics inside
this #each. I''m using #splice method inside some conditional matches.
this.removeItems = function(item) {
var _myArray = myArray.clone();
_myArray.each( function(content, index) {
....
if(content.regItem == item) { delete content;
myArray.splice(index,1); }
....
});
}
If all .regItem''s equal to item''s, only then myArray should be
empty.
On Jun 24, 12:21 am, "Frederick Polgardy"
<f...-SMQUYeM9IBBWk0Htik3J/w@public.gmane.org>
wrote:> You could always do it recursively. ;-) If only JavaScript had tail
> recursion!
>
> function eraseArray(a) {
> delete a[0];
> if (a.length > 0)
> eraseArray(a.slice(1));
>
> }
>
> -Fred
>
> On Mon, Jun 23, 2008 at 4:02 PM, T.J. Crowder
<t...-MUGVhKWuB3Yd9SLi6J12IkEOCMrvLtNR@public.gmane.org>
> wrote:
>
>
>
> > > I''ve solved this issue following:
>
> > But....why?! Just set the length to zero. No need for all of the
> > cloning and splicing!
>
> --
> Science answers questions; philosophy questions answers.
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There''s a #reject for cases like this:
this.removeItems = function(item) {
myArray = myArray.reject(function(_item, i) {
return _item.regItem == item;
})
}
- kangax
On Jun 23, 6:59 pm, mocambo <moca...-S7FoVGKkKTI@public.gmane.org>
wrote:> Sorry for confusion !
>
> My sample here was simplified. Actually I have much more logics inside
> this #each. I''m using #splice method inside some conditional
matches.
>
> this.removeItems = function(item) {
>
> var _myArray = myArray.clone();
>
> _myArray.each( function(content, index) {
> ....
> if(content.regItem == item) { delete content;
> myArray.splice(index,1); }
> ....
> });
>
> }
>
> If all .regItem''s equal to item''s, only then myArray
should be empty.
>
> On Jun 24, 12:21 am, "Frederick Polgardy"
<f...-SMQUYeM9IBBWk0Htik3J/w@public.gmane.org> wrote:
>
> > You could always do it recursively. ;-) If only JavaScript had tail
> > recursion!
>
> > function eraseArray(a) {
> > delete a[0];
> > if (a.length > 0)
> > eraseArray(a.slice(1));
>
> > }
>
> > -Fred
>
> > On Mon, Jun 23, 2008 at 4:02 PM, T.J. Crowder
<t...-MUGVhKWuB3Yd9SLi6J12IkEOCMrvLtNR@public.gmane.org>
> > wrote:
>
> > > > I''ve solved this issue following:
>
> > > But....why?! Just set the length to zero. No need for all of
the
> > > cloning and splicing!
>
> > --
> > Science answers questions; philosophy questions answers.
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