Monday, April 22, 2013

Search int in an Array

To search a int in an array, we can use the code:

Arrays.asList(<Array of Integer>).indexOf(<target int>)

Where Arrays.asList(<Array of Integer>) returns a fixed-size list backed by the specified array. indexOf(<target int>) returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. Please notice that <Array of Integer> can be Integer[], not int[]; because int is a primitive types, a special data types built into the language; they are not objects created from a class.


package javatestarray;

import java.util.Arrays;

 * @web
public class JavaTestArray {
    final static int[] Array_int = {1, 2, 3, 4, 5};
    final static Integer[] Array_Integer = {1, 2, 3, 4, 5};

    public static void main(String[] args) {
        int indexIn_Array_int = Arrays.asList(Array_int).indexOf(3);
        System.out.println("indexIn_Array_int = " + indexIn_Array_int);
        //not work! -1 will be returned.
        int indexIn_Array_Integer = Arrays.asList(Array_Integer).indexOf(3);
        System.out.println("indexIn_Array_Integer = " + indexIn_Array_Integer);
        //2 will be returned

No comments:

Post a Comment