How to use ArrayList's get() method

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长发绾君心
长发绾君心 2021-01-04 13:27

I\'m new to java (& to OOP too) and I\'m trying to understand about the class ArrayList but I don\'t understand how to use the get(). I tried searching in net, but could

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  • 2021-01-04 13:49

    To put it nice and simply, get(int index) returns the element at the specified index.

    So say we had an ArrayList of Strings:

    List<String> names = new ArrayList<String>();
    names.add("Arthur Dent");
    names.add("Marvin");
    names.add("Trillian");
    names.add("Ford Prefect");
    

    Which can be visualised as: Where 0, 1, 2, and 3 denote the indexes of the ArrayList.

    Say we wanted to retrieve one of the names we would do the following: String name = names.get(1); Which returns the name at the index of 1.

    So if we were to print out the name System.out.println(name); the output would be Marvin - Although he might not be too happy with us disturbing him.

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  • 2021-01-04 13:51

    You use List#get(int index) to get an object with the index index in the list. You use it like that:

    List<ExampleClass> list = new ArrayList<ExampleClass>();
    list.add(new ExampleClass());
    list.add(new ExampleClass());
    list.add(new ExampleClass());
    ExampleClass exampleObj = list.get(2); // will get the 3rd element in the list (index 2);
    
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  • 2021-01-04 13:59

    Would this help?

    final List<String> l = new ArrayList<String>();
    for (int i = 0; i < 10; i++) l.add("Number " + i);
    for (int i = 0; i < 10; i++) System.out.println(l.get(i));
    
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  • 2021-01-04 14:04

    Here is the official documentation of ArrayList.get().

    Anyway it is very simple, for example

    ArrayList list = new ArrayList();
    list.add("1");
    list.add("2");
    list.add("3");
    String str = (String) list.get(0); // here you get "1" in str
    
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  • 2021-01-04 14:05

    ArrayList get(int index) method is used for fetching an element from the list. We need to specify the index while calling get method and it returns the value present at the specified index.

    public Element get(int index)
    

    Example : In below example we are getting few elements of an arraylist by using get method.

    package beginnersbook.com;
    import java.util.ArrayList;
    public class GetMethodExample {
       public static void main(String[] args) {
           ArrayList<String> al = new ArrayList<String>();
           al.add("pen");
           al.add("pencil");
           al.add("ink");
           al.add("notebook");
           al.add("book");
           al.add("books");
           al.add("paper");
           al.add("white board");
    
           System.out.println("First element of the ArrayList: "+al.get(0));
           System.out.println("Third element of the ArrayList: "+al.get(2));
           System.out.println("Sixth element of the ArrayList: "+al.get(5));
           System.out.println("Fourth element of the ArrayList: "+al.get(3));
       }
    }
    

    Output:

    First element of the ArrayList: pen
    Third element of the ArrayList: ink
    Sixth element of the ArrayList: books
    Fourth element of the ArrayList: notebook
    
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