CODEWITHSUNDEEP
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Streetboy
Streetboy

Reputation: 4401

Getting List elements

i have an ArrayList with elements for example:

[a,b,c,d,e,f,g,h];

and need to take elements [a,b,c] also it should be an ArrayList and remove them from first List and again i take some elements from first list after i take i remove them.

So what is the best way (considering a time) to do this job ? I mean i should iterate over elements or should convert to array and than work with it ?

maybe there are some fast way to do this ?

Thanks.

Upvotes: 0

Views: 242

Answers (2)

ataylor
ataylor

Reputation: 66109

Create a new list using subList() to get a view into the first, then use clear() on the subList. Example:

subList = originalList.subList(0, 3);
newList = new ArrayList(subList);
subList.clear();

This is much more efficient than iterating over the original list removing one element at a time since removing an element from an ArrayList involves shifting all the elements. Using a subList does the shift just once.

Upvotes: 1

Eran Zimmerman Gonen
Eran Zimmerman Gonen

Reputation: 4507

You could use the sublist method to split this list into two (making two calls to sublist).

Upvotes: 0

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