Removing from an array

HI all
Can somebody give me the best way from performance point of view, how to delete an element from an array.
THanks
kundan

Moving this to the Performance forum...

Just to clarify a bit, does this include searching for the item? If so, is the array sorted? When something is removed from the middle, do the components further down the array all need to slide over a notch, preserving the order, or does anything need to fill in the new empty space?

Originally posted by Stefan Wagner:
foo[3]=null;

Well, yeah, this is certainly the fastest. Wether it's actually doing what you want depends on your answers to Dirk questions, though...

HI Derk
Yes order need to me maintained and the array is sorted.
What can be the solution then.I dont want to go with null option.
THanks
kundan

Do you even need to use an array? Sounds like a TreeSet may be worth considering here (unless you need to allow duplicates). Alternately, perhaps a LinkedList, or even ArrayList. Depends what else you're doing with the data. If you must use an array, then you should probably use System arraycopy() to shift the latter part of the array one slot to the left, as efficiently as possible. You'll have a null at the end, but that's the price of using an array, I think. Unless you want to recopy the whole array to another which is one element smaller, which seems rather wasteful from a performance perspective.

I suspect the solution is different depending on how many elements you want to remove. I would add "how many elements have to be removed" to Dirk's questions. If the number to be removed is a large fraction of the total, building a new array is probably fastest.

Bill

well - without wholes wanted in the array, use ArrayList, and:

arrayList.remove (3);

and

arrayList.toArray ();

if someone needs an array.