Determine whether an array is empty in java-JavaBase-php.cn

Determine whether an array is empty in java

Arrays are one of the important data structures for every programming language. Of course, different languages implement and process arrays differently. Arrays provided in the Java language are used to store fixed-size elements of the same type.

Java determines whether the array is empty:

public class Main { public static void main(String[] args) { int[] array1 = new int[]{}; //被当成 {0} if (array1 == null) { System.out.println("array1 == null"); } System.out.println(array1.length);//行数 if (array1.length == 0) { System.out.println("array1.length == 0"); } System.out.println("-----------------------------"); int[][] array2 = new int[][]{{}}; //被当成 {{0},{},{}} if (array2 == null) { System.out.println("array2 == null"); } System.out.println(array2.length);//行数 if (array2.length == 0) { System.out.println("array2.length == 0"); } if (array2[0].length == 0) {//第一行的长度 System.out.println("array2[0].length == 0"); } System.out.println("-----------------------------"); Integer[] array3 = new Integer[]{}; //被当成 {0} if (array3 == null) { System.out.println("array3 == null"); } System.out.println(array3.length);//行数 if (array3.length == 0) { System.out.println("array3.length == 0"); } System.out.println("-----------------------------"); int[][] array4 = new int[][]{{}}; //被当成 {{0},{},{}} if (array4 == null) { System.out.println("array4 == null"); } System.out.println(array4.length);//行数 if (array4.length == 0) { System.out.println("array4.length == 0"); } if (array4[0].length == 0) {//第一行的长度 System.out.println("array4[0].length == 0"); } } } /*输出： 0 array1.length == 0 ----------------------------- 1 array2[0].length == 0 ----------------------------- 0 array3.length == 0 ----------------------------- 1 array4[0].length == 0*/

Copy after login

One-dimensional array needs to be judged according to the length of the array. If it is 0, it is empty, and vice versa;

Two-dimensional array needs to Judging based on the array length in the first line, if it is 0, it is empty, and vice versa;

For more java knowledge, please pay attention tojava basic tutorial.

The above is the detailed content of Determine whether an array is empty in java. For more information, please follow other related articles on the PHP Chinese website!