打印多維數組Java

Question

我只想通過for循環打印我的空數組。

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10

怎么了？

int NYEARS = 5;
int NRATES = 3;

double[][] balancee = new double[NYEARS][NRATES];
for (int i = 0; i < NYEARS; i++) {
    for (int j = 0; j < NRATES; j++) {
        System.out.print(balance[NYEARS][NRATES] + " ");
        System.out.println();
    }
}

Answer 1

您應該使用循環索引訪問數組元素，而不是數組維度：

for (int i = 0; i < NYEARS; i++) {
    for (int j = 0; j < NRATES; j++) {
        System.out.print(balance[i][j] + " ");
        System.out.println();
    }
}

Answer 2

您的解決方案將導致java.lang.ArrayIndexOutOfBoundsException: 5您也有錯字balance而您的意思是balancee ：

因此，您必須使用balancee.length和balancee[i].length而不是balance[NYEARS][NRATES] ，所以必須使用balancee[i][j]像這樣：

for (int i = 0; i < balancee.length; i++) {
    for (int j = 0; j < balancee[i].length; j++) {
        System.out.print(balancee[i][j] + " ");
        System.out.println();
    }
}

Answer 3

當我不需要對它們的索引進行算術運算時，我通常更喜歡foreach

for (double[] x : balancee) { 
    for (double y : x) { 
        System.out.print(y + " ");
 }        
    System.out.println(); 
 }

更重要的是，希望您能balance[NYEARS][NRATES]為什么不能使用balance[NYEARS][NRATES] 。

Answer 4

只需使用內置的Arrays.deepToString()

int[][] foo = { null, {}, { 1 }, { 2, 3 } };
System.out.println(Arrays.deepToString(foo));

產量

[null, [], [1], [2, 3]]

Answer 5

int NYEARS = 5; //This is the size
int NRATES = 3; //This is the size

double[][] balancee = new double[NYEARS][NRATES]; //<-- balancee vs balance



for (int i = 0; i < NYEARS; i++) {
for (int j = 0; j < NRATES; j++) {
    System.out.print(balance[NYEARS][NRATES] + " "); //<-- use i and j instead of size. 
    System.out.println();
    }
}