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2 Replies Latest reply: Feb 27, 2013 12:48 AM by gimbal2 RSS

How to use an Arraylist of Int arrays

HawkerHunter Newbie
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I have to capture arrays of size two within another array like {[1,2],[2,3],[3,4],............,[(n-1),n]}
I can set the size of the second array to two but the size of the main array shall be calculated at run time.
So I decided to take the main array as an Array List so that size can dynamically increase.

I would like to know how to enter the elements to the secondary array and how to add the secondary arrays to the main array list.
Also I would like to know how to read the elements of the secondary or internal array and compare with another elements of the secondary array.

Regards
Hawker Hunter
  • 1. Re: How to use an Arraylist of Int arrays
    Kayaman Guru
    Currently Being Moderated
    If you know the arrays are always going to be size two, I'd recommend creating a Pair class to hold the variables (it's annoying that the SDK doesn't have a ready made one).
    It's cleaner that way, even though it's possible to do with arrays too.

    As for your question about basic usage of the ArrayList class, I refer you to the javadoc and the numerous examples on the internet.
  • 2. Re: How to use an Arraylist of Int arrays
    gimbal2 Guru
    Currently Being Moderated
    HawkerHunter wrote:
    I have to capture arrays of size two within another array like {[1,2],[2,3],[3,4],............,[(n-1),n]}
    I can set the size of the second array to two but the size of the main array shall be calculated at run time.
    So I decided to take the main array as an Array List so that size can dynamically increase.

    I would like to know how to enter the elements to the secondary array
    First obtain the array from the arraylist with its get() method, then index into it like you normally would index into an array
    and how to add the secondary arrays to the main array list.
    With the list add() method

    http://docs.oracle.com/javase/7/docs/api/java/util/ArrayList.html
    Also I would like to know how to read the elements of the secondary or internal array and compare with another elements of the secondary array.
    Use two loops? Hard to give a specific answer to such a non-specific requirement.

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