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Thread: how to remove items of an arraylist

  1. #1
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    Default how to remove items of an arraylist

    hey guys,
    i got a little question about my code...
    does the code removes the int of the arraylist? and gives it a true value out if it is removed?
    	public boolean kL(int ktonummer){
    		if (finKntoIdex(ktonummer) > 0) { 
    			konten.remove(ktonummer);
    			return true;
    		}
    		else 
    		return false;
    	}
    	private int finKntoIdex(int ktonummer){
    		for(int i = 0;i<konten.size();i++){
    			if(konten.get(i).getKontonummer() == ktonummer){
    				return i;
    			}
    		}
    		return -1;
    	}
     
    private ArrayList<Konto> konten = new ArrayList<Konto>();
    Last edited by Norm; December 16th, 2012 at 12:58 PM. Reason: changed quote to code tags


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: how to remove items of an arraylist

    Have you tried testing the kL() method to see what happens when it is executed?
    Create a small test program with an arraylist, call the kL() method to have it remove an element and then print out the arraylist to see if the element has been removed.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: how to remove items of an arraylist

    yes thanks mate it worked !

    a other question my toString method will not work...
    @Override
    public String toString(){
    return String.format("Kontonummer: %s, Nachname: %s" , kten.kontonummer + konten.nachname);


    }

    private ArrayList<Konto> kten = new ArrayList<Konto>();

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: how to remove items of an arraylist

    toString method will not work...
    Please explain.
    Post full text of any error messages.
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: how to remove items of an arraylist

    kten.kontonummer and kten.nachname cannot be resolved or is not a field ...
    but i have declared it in a other class

  6. #6
    Super Moderator Norm's Avatar
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    Default Re: how to remove items of an arraylist

    Are you saying the compiler can not find those variables?
    Some possible reasons:
    Are they defined?
    Did you spell the names correctly?
    Are the definitions in scope where you are trying to use them?

    Without seeing the source, I have no idea why.


    BTW what you posted is not the full text of the compiler's error messages.
    Here is a sample:
    TestSorts.java:138: cannot find symbol
    symbol  : variable var
    location: class TestSorts
             var = 2;
             ^
    If you don't understand my answer, don't ignore it, ask a question.

  7. #7
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    Default Re: how to remove items of an arraylist

    yes they are in the right scope but not on the same class
    the first code is at the class bank.
    @Override
    public String toString(){
    return String.format("Kontonummer: %s, Nachname: %s" , kten.kontonummer + kten.nachname);


    }

    private ArrayList<Konto> kten = new ArrayList<Konto>();
    there i work with the arraylist for example
    public boolean kontoLoeschen(int ktonummer){

    if (findeKontoIndex(ktonummer) > 0) {
    kten.remove(ktonummer);
    return true;
    }
    else
    return false;
    or

    private int findeKontoIndex(int ktonummer){
    for(int i = 0;i<konten.size();i++){
    if(kten.get(i).getKtonummer() == ktonummer){
    return i;
    }
    }
    return -1;
    }

    }
    but i have declared it in a other class called kten or prson
    public String getNachname() {
    return nachname;
    }

  8. #8
    Super Moderator Norm's Avatar
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    Default Re: how to remove items of an arraylist

    Please post the full text of the compiler's error messages.
    If you don't understand my answer, don't ignore it, ask a question.

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