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Thread: Arraylist issue

  1. #1
    Bellyfish is offline Member
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    Apr 2012
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    Default Arraylist issue

    Hey, having an issue with arraylists.

    I have some code which requires me to pass an arraylist into a method and then clear that arraylist.
    However whenever i clear it an empty arraylist is just passed into the method (which is understandable)

    Is there a way i can retain the arraylist data? Ive tried creating a new instance of the arraylist and making it equal to the old one but this is cleared when the old one is cleared. Is it possible to do even?

    (sorry if this is unclear, will provide code if this is gibberish)

  2. #2
    wsaryada is offline Senior Member
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    Jun 2007
    Bali, Indonesia
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    Default Re: Arraylist issue

    You need to copy the content of the old ArrayList into the new one. If you just make the new one equal to the old ArrayList by using the assignment operator, you simply tell the new ArrayList to point to the old ArrayList. It will referring the same object. So whatever you do the the first ArrayList will affect the other.
    Bellyfish likes this.

  3. #3
    Bellyfish is offline Member
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    Apr 2012
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    Default Re: Arraylist issue

    Cheers for explaining it to me, was now able to create a new distinct arraylist.
    Thanks again!

  4. #4
    Tolls is offline Moderator
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    Default Re: Arraylist issue

    ArrayList has a constructor that accepts another Collection (maybe just a List) as a parameter which copies the contents from the old one to the new one.
    Please do not ask for code as refusal often offends.

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