Java ArrayList contains() method với ví dụ cụ thể

ArrayList contains() sử dụng để kiểm tra phần tử có chứa trong mảng hay không.

public boolean contains(Object element)

Trả về true nếu tìm thấy, false nếu phần tử không chứa trong ArrayList.

Ví dụ

 import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {

        ArrayList<String> al = new ArrayList<String>();
        al.add("pen");
        al.add("pencil");
        al.add("ink");
        al.add("notebook");

        System.out.println("ArrayList contains the string 'ink pen': "
                + al.contains("ink pen"));
        System.out.println("ArrayList contains the string 'pen': "
                + al.contains("pen"));
        System.out.println("ArrayList contains the string 'pencil': "
                + al.contains("pencil"));
        System.out.println("ArrayList contains the string 'book': "
                + al.contains("book"));

        ArrayList<Integer> al2 = new ArrayList<Integer>();
        al2.add(1);
        al2.add(99);
        al2.add(56);
        al2.add(13);
        al2.add(44);
        al2.add(6);

        System.out.println("'1' is present in arraylist: " + al2.contains(1));
        System.out.println("'55' is present in arraylist: " + al2.contains(55));
        System.out.println("'44' is there in arraylist: " + al2.contains(44));
        System.out.println("'7' is there in arraylist: " + al2.contains(7));
    }
}

Output: 

ArrayList contains the string ‘ink pen’: false
ArrayList contains the string ‘pen’: true
ArrayList contains the string ‘pencil’: true
ArrayList contains the string ‘book’: false
‘1’ is present in arraylist: true
’55’ is present in arraylist: false
’44’ is there in arraylist: true
‘7’ is there in arraylist: false

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