英文:
How to initialize a multidimensional array on the go in java
问题
我有一个多维数组，其中第二维的长度不总是相同的。
是否可能初始化一个数组，您首先可以像这样创建第一个部分
我正在使用这个数组来定义矩阵中每行的长度。
int[] config = {4,4,4,3,2,4};
boolean[][] array = new boolean[config.length][];
然后在循环遍历数组并使用所需的长度创建子数组？
for(int i = 0; i < config.length; i++)
array[i] = new boolean[config[i]];
附注：我不会使用ArrayList。
英文:
I have a multidimensional array where the second dimension is not always the same length.
Is it possible to initialize an array where you first create the first part like this
I am using this array to define the length of each row in the matrix.
int[] config = {4,4,4,3,2,4};
boolean[][] array = new boolean[config.lenght][];
and then after loop over the array and create the subarrays with the desired length?
for(int i = 0; i<config.length; i++)
boolean[i][] = new boolean[config[i]];
PS: I will not use ArrayList
答案1
得分: 1
public static int[][] generate(int[] config) {
int[][] arr = new int[config.length][];
Random random = new Random();
for (int row = 0; row < arr.length; row++) {
arr[row] = new int[config[row]];
for (int col = 0; col < arr[row].length; col++)
arr[row][col] = random.nextInt(100);
}
return arr;
}
Output:
[
[97, 80, 78, 88],
[31, 97, 34, 39],
[67, 92, 89, 0],
[29, 96, 72],
[68, 77],
[7, 65, 68, 51]
]
英文:
public static int[][] generate(int[] config) {
int[][] arr = new int[config.length][];
Random random = new Random();
for (int row = 0; row < arr.length; row++) {
arr[row] = new int[config[row]];
for (int col = 0; col < arr[row].length; col++)
arr[row][col] = random.nextInt(100);
}
return arr;
}
Output:
[
[97, 80, 78, 88],
[31, 97, 34, 39],
[67, 92, 89, 0],
[29, 96, 72],
[68, 77],
[7, 65, 68, 51]
]
答案2
得分: 0
可以将任何单个的 D 数组赋值给相同类型的 2D 数组。
int[] s = {1,2,3,4,5,6};
int[][] twoD = new int[s.length][];
for (int i = 0; i < v.length; i++) {
twoD[i] = new int[]{s[i]}; // `s` 数组中一个元素的新数组
}
for (int[] s : twoD) {
System.out.println(s);
}
输出
[1]
[2]
[3]
[4]
[5]
[6]
或者
System.out.println(Arrays.deepToString(twoD));
输出
[[1], [2], [3], [4], [5], [6]]
英文:
You can assign any single D array to a 2D array of the same type.
int[] s = {1,2,3,4,5,6};
int[][] twoD = new int[s.length][];
for (int i = 0; i < v.length; i++) {
twoD[i] = new int[]{s[i]}; // new array of one element of the `s` array
}
for ( int[] s : twoD) {
System.out.println(s);
}
Prints
[1]
[2]
[3]
[4]
[5]
[6]
or
System.out.println(Arrays.deepToString(twoD));
Prints
[[1], [2], [3], [4], [5], [6]]
</details>
# 答案3
**得分**: 0
以下是翻译好的部分：
我不完全理解这个问题，但我有一个类似这样的解决方案建议。
```java
int[] config = {4,4,4,3,2,4};
int[][] array = new int[config.length][config.length];
for(int i = 0 ; i<config.length ; i++){
array[i][0] = config[i];
}
数组输出：
400000
400000
400000
300000
200000
400000
英文:
I do not fully understand the question, but I have a suggestion for a solution like this.
int[] config = {4,4,4,3,2,4};
int[][] array = new int[config.length][config.length];
for(int i = 0 ; i<config.length ; i++){
array[i][0] = config[i];
}
array output:
400000
400000
400000
300000
200000
400000
答案4
得分: 0
你还可以使用流：
int[] config = {4, 4, 4, 3, 2, 4};
boolean[][] myArr = Arrays.stream(config).mapToObj(i -> new boolean[i]).toArray(boolean[][]::new);
for (boolean[] b : myArr) {
System.out.println(Arrays.toString(b));
}
英文:
You can also use streams:
int[] config = {4,4,4,3,2,4};
boolean[][] myArr = Arrays.stream(config).mapToObj(i -> new boolean[i]).toArray(boolean[][]::new);
for(boolean[] b : myArr){
System.out.println(Arrays.toString(b));
}
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