英文:
(java) How to iterate over double[][] 2d array using for each loop?
问题
for (double[] row: array) {
for (double x: row) {
for (double[] col: array) {
for (double y: col) {
System.out.println(array[(int)x][(int)y]);
}
}
}
}
英文:
for (double[] row: array) {
for (double x: row) {
for (double[] col: array) {
for (double y: col) {
System.out.println(array[x][y]);
}
}
}
}
extracted from my code.When I compile in terminal I receive "incompatible types: possible lossy conversion from double to int. I am trying to print out a double[][] as a matrix.
I am required to use afor each loop I know that the indexes have to be ints but how would I make sure they are when i can 't convert doubles to ints?
答案1
得分: 3
你可以像这样做：
// 首先迭代每一行
for (double[] rows : array) {
// 然后对于该行，打印每个值。
for (double v : rows) {
System.out.print(v + " ");
}
// 在每行后打印换行符
System.out.println();
}
对于
double[][] a = new double[][] { { 1,2,3 }, {4,5,6 }, { 7,8,9 } };
打印结果为
1.0 2.0 3.0
4.0 5.0 6.0
7.0 8.0 9.0
英文:
You can do it like this:
// first iterate each row
for (double[] rows : array) {
// then for that row, print each value.
for (double v : rows) {
System.out.print(v + " ");
}
// print new line after each row
System.out.println();
}
For
double[][] a = new double[][] { { 1,2,3 }, {4,5,6 }, { 7,8,9 } };
Prints
1.0 2.0 3.0
4.0 5.0 6.0
7.0 8.0 9.0
</details>
# 答案2
**得分**: 2
一个"for each"循环遍历值，而不是索引。此外，你只需要两个嵌套循环。
```java
final double[][] array = {{1, 2}, {3, 4}, {5, 6}};
for (double[] row: array) {
for (double element: row) {
System.out.println(element);
}
}
英文:
A for each loop loops over the values, not the indexes. Moreover, you only need two nested loops.
final double[][] array = {{1, 2}, {3, 4}, {5, 6}};
for (double[] row: array) {
for (double element: row) {
System.out.println(element);
}
}
答案3
得分: 1
这是遍历二维数组的正确方式：
for (double[] row : array) {
for (double value : row) {
System.out.println(value);
}
}
英文:
This is the right way to loop over 2d array
for (double [] row : array) {
for (double value : row) {
System.out.println(value);
}
}
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