Good way to remove Vector elements from end?

Thread view:

Jim Bancroft - 29 Mar 2006 07:30 GMT

Hi,

I'd like to remove all elements in my vector from, say, index i to the end.
Is there a good way of doing this? I have a kludge which may or may not do
the job (haven't tested yet), but I'm thinking there's a better way:

for(int x=(myVector.size()-1); x >= i; x--){
myVector.removeElementAt(x);

}

Even looking at that makes me squirm, and there's got to be another
approach. If you know of one I'm all ears. Thanks!

Reply to this Message

opalpa@gmail.com opalinski from opalpaweb - 29 Mar 2006 12:00 GMT

myVector.setSize(i);

Opalinski
opalpa@gmail.com
http://www.geocities.com/opalpaweb/

Reply to this Message

Thomas Hawtin - 29 Mar 2006 15:43 GMT

> I'd like to remove all elements in my vector from, say, index i to the end.
> Is there a good way of doing this? I have a kludge which may or may not do
[quoted text clipped - 4 lines]
>
> }

In general you can remove a range from a List with subList and then clear:

myList.subList(from, to).clear();

It does create one tiny little object. These days the cost of allocating
a tiny object is small.

Tom Hawtin

Signature

Unemployed English Java programmer
http://jroller.com/page/tackline/

Reply to this Message

Roedy Green - 29 Mar 2006 19:03 GMT

On Wed, 29 Mar 2006 15:43:08 +0100, Thomas Hawtin
<usenet@tackline.plus.com> wrote, quoted or indirectly quoted someone
who said :

>In general you can remove a range from a List with subList and then clear:
>
> myList.subList(from, to).clear();

clearing and removing are different operations. Is it possible to use
sublist to remove?

Signature

Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

Reply to this Message

Thomas Hawtin - 29 Mar 2006 18:18 GMT

> On Wed, 29 Mar 2006 15:43:08 +0100, Thomas Hawtin
> <usenet@tackline.plus.com> wrote, quoted or indirectly quoted someone
[quoted text clipped - 4 lines]
> clearing and removing are different operations.
> sublist to remove?

clear removes all the elements from a collection. "Clear" does sound
like nulling out, but isn't.

> Is it possible to use
> sublist to remove?

"The returned list supports all of the optional list operations
supported by this list."
<http://download.java.net/jdk6/docs/api/java/util/List.html#subList(int,
int)>

(Which, coincidentally, also contains almost exactly the same example as
I wrote above.)

Tom Hawtin

Signature

Unemployed English Java programmer
http://jroller.com/page/tackline/

Reply to this Message

Oliver Wong - 29 Mar 2006 16:16 GMT

> Hi,
>
[quoted text clipped - 10 lines]
> Even looking at that makes me squirm, and there's got to be another
> approach. If you know of one I'm all ears. Thanks!

http://java.sun.com/j2se/1.5.0/docs/api/java/util/Vector.html#setSize(int)

- Oliver

Reply to this Message

Roedy Green - 29 Mar 2006 18:58 GMT

>I'd like to remove all elements in my vector from, say, index i to the end.
>Is there a good way of doing this? I have a kludge which may or may not do
[quoted text clipped - 4 lines]
>
> }

ArrayList.removeRange(int fromIndex, int toIndex)
is protected so you can't use it.

Your way is the best I know of that does the least shuffling.

See http://mindprod.com/jgloss/arraylist.html#REMOVING

Signature

Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

Reply to this Message

Thomas Hawtin - 29 Mar 2006 18:19 GMT

>
> ArrayList.removeRange(int fromIndex, int toIndex)
> is protected so you can't use it.

At least not unless you subclass.

Tom Hawtin

Signature

Unemployed English Java programmer
http://jroller.com/page/tackline/

Reply to this Message

Good way to remove Vector elements from end?

Free Magazines