Detailed explanation of Java two-dimensional array: Declaration and initialization of two-dimensional array, and obtaining the value of two-dimensional array
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Java
Create a 2D array
type array[][]; type[][] array;
int[][] age; char[][] sex;
Initialize 2D array
array=new type[][]{值 1,值 2,值 3,…,值 n}; array=new type[][]{new 构造方法(参数列),…}; type[][] array={{第1行第1列的值,第1行第2列的值,…},{第2行第1列的值,第2行第2列的值,…};
Example 1
int[][] temp; temp=new int[][] { {1,2},{3,4} };
int[][] temp; temp=new int [][] { {new int(1),new int(2)},{new int(3),new int(4)} };
int[][] temp={{1,4}};
Get a single element
array[i-1][j-1];
Example 2
public static void main(String[] args) { double[][] class_score={{10.0,99,99},{100,98,97},100,99.5},{99.5,98.5}}; System.out.println("第二行第二列元素的值:"+class_score[1][1]); System.out.println("第四行第一列元素的值:"+class_score[3][0]); }
第二行第二列元素的值:98.0 第四行第一列元素的值:99.5
Get all elements
Example 3
public static void main(String[] args) { double[][] class_score={{100,98.5 }}; for(int i=0;i<class_score.length;i++) { //遍历行 for(int j=0;j<class_score[i].length;j++) { System.out.println("class_score["+i+"]["+j+"]="+class_score[i][j]); } } }
class_score[0][0]=100.0 class_score[0][1]=99.0 class_score[0][2]=99.0 class_score[1][0]=100.0 class_score[1][1]=98.0 class_score[1][2]=97.0 class_score[2][0]=100.0 class_score[2][1]=100.0 class_score[2][2]=99.5 class_score[3][0]=99.5 class_score[3][1]=99.0 class_score[3][2]=98.5
Example 4
public class Test11 { public static void main(String[] args) { //创建一个二维矩阵 int[][] matrix=new int[5][5]; //随机分配值 for(int i=0;i<matrix.length;i++) { for(int j=0;j<matrix[i].length;j++) { matrix[i][j]=(int)(Math.random()*10); } } System.out.println("下面是程序生成的矩阵\n"); //遍历二维矩阵并输出 for(int k=0;k<matrix.length;k++) { for(int g=0;g<matrix[k].length;g++) { System.out.print(matrix[k][g]+""); } System.out.println(); } } }
34565 96033 48741 10583 63985
Gets the entire line of elements
Example 5
public static void main(String[] args) { double[][] class_score={{100,98.5}}; Scanner scan=new Scanner(system.in); System.out.println("当前数组只有"+class_score.length+"行,您想查看第几行的元素?请输入:"); int number=scan.nextInt(); for(int j=0;j<class_score[number-1].length;j++) { System.out.println("第"+number+"行的第["+j+"]个元素的值是:"+class_score[number-1][j]); } }
当前数组只有4行,您想查看第几行的元素?请输入: 3 第3行的第[0]个元素的值是:100.0 第3行的第[1]个元素的值是:100.0 第3行的第[2]个元素的值是:99.5
Gets the entire column element
Example 6
public static void main(String[] args) { double[][] class_score={{100,98.5}}; Scanner scan=new Scanner(system.in); System.out.println("您要获取哪一列的值?请输入:"); int number=scan.nextInt(); for(int i=0;i<class_score.length;i++) { System.out.println("第 "+(i+1)+" 行的第["+number+"]个元素的值是"+class_score[i][number]); } }
您要获取哪一列的值?请输入: 2 第 1 行的第[2]个元素的值是99.0 第 2 行的第[2]个元素的值是97.0 第 3 行的第[2]个元素的值是99.5 第 4 行的第[2]个元素的值是98.5
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