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Thread: How display the first elements and last elements of collection of objects?

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    Default How display the first elements and last elements of collection of objects?

    For example we have the object created with the class that contain id, name and salary. The objects is posted by the salary and names if the salary is the same. What to do. We could not use indexes in arraylist. New for operator display only the whole set. But i need for example the 5 first element and 3 lasts?


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    Default Re: How display the first elements and last elements of collection of objects?

    What class holds the collection of objects? What methods does that class have that would help you get the desired objects so you can display them?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How display the first elements and last elements of collection of objects?

    I think most fittable class in this situation is Arraylist. It has the method get(). But it is awkward to show every item. Especially the last ones. The last is possible if it possible to define the size of Array by the same name-size(). But do this method has it? This is very simple in standart array. Maybe transform the arraylist to simple array of objecs but how? For example I create the arraylist by such way Arraylist (<Object>?) workers=new Arqaylist .. Them add by:workers.add(1, "smith", 100)

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    Default Re: How display the first elements and last elements of collection of objects?

    We could not use indexes in arraylist.
    Why not? Have you reviewed the ArrayList API for all that can be done?

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    Default Re: How display the first elements and last elements of collection of objects?

    Could you show how to do it in this collection Workers. It very simple as it is really to be? I surfed internet and say question about the first and the last one. And the answers were not so evident. Here the task is even comlex.

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    Default Re: How display the first elements and last elements of collection of objects?

    about the first and the last one
    The index for the first one is 0 and the index for the last one is the size-1
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How display the first elements and last elements of collection of objects?

    Or it is very simple with indexes that begins at 0 and ends with i-1. So olny by one: system.out.println(workers.get(1).to sring). Or i am not correctu in displaying it?

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    Default Re: How display the first elements and last elements of collection of objects?

    Sorry, I don't understand what the problem is.
    What happens when you compile and execute the code?
    If the code is getting errors, copy the full text of the error message and paste it here.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How display the first elements and last elements of collection of objects?

    I have not code. But you could make a simple tip as a Arraylist has a substrig(index1,index2) method to display or extract appropriate objects in the sequence. I this situation I have question what other collection is applicable to save the objects of such workers class with different types of variables-SET? LinkedList?

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    Default Re: How display the first elements and last elements of collection of objects?

    What collection you use to save a list of objects would depend on how the code needs to access that list and on other characteristics of the data being saved.
    If you don't understand my answer, don't ignore it, ask a question.

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