Question

我想创建2d数组并用元素填充它。在每个子阵列中应该是一个随机数字。

    var n = 11; //number of elements in subarray
    var listofnumbers = [];
    var rows = [];
    var cols = [];
    var rand;

    //fill listofnumbers array by numbers
    for(i=0; i<=n-1; i++) {
        listofnumbers[i] = n - i;
    }
    //reverse listofnumbers array
    listofnumbers.reverse();

    //fill array 'cols' with another arrays
    for(k=0; k<=n-1; k++) {

        rand = listofnumbers[Math.floor(Math.random()*listofnumbers.length)]; // random digit from listofnumbers array

        for(j=0; j<=n-1; j++) {
            if(j == rand-1) {
                rows[j] = rand-1;
            } else {
                rows[j] = "*";
            }
        }

        console.log("rowsarr at iteration " + k + ": " + rows);

        cols[k] = rows;

        console.log("colsarr at iteration " + k + ": " + cols);
    }

由于某种原因，输出类似于：

rowsarr at iteration 0: *,*,*,*,*,*,*,7,*,*,*
colsarr at iteration 0: *,*,*,*,*,*,*,7,*,*,*
rowsarr at iteration 1: *,*,*,*,*,*,*,7,*,*,*
colsarr at iteration 1: *,*,*,*,*,*,*,7,*,*,*,*,*,*,*,*,*,*,7,*,*,*
rowsarr at iteration 2: *,*,*,3,*,*,*,*,*,*,*
colsarr at iteration 2: *,*,*,3,*,*,*,*,*,*,*,*,*,*,3,*,*,*,*,*,*,*,*,*,*,3,*,*,*,*,*,*,*

等等，直到n次迭代。

问题1：为什么数组“cols”通过最后生成的“rows”数组填充所有元素？它应该将最后生成的数组“行”推送到最后。

问题2：我怎样才能获得像cols = [[n，n，n，n，n]，[n，n，n，n，n]，...]这样的二维数组。现在我只有cols = [n，n，n，n，n，n，n，n，n，n，n，n，n]？

目前，我的代码如下所示：https://jsfiddle.net/qqf3fL5L/10/

Answer 1

<强>解决方案：

你应该在第一个循环中声明数组'rows'，如下所示：https://jsfiddle.net/qqf3fL5L/12/

for(k=0; k<n; k++) {
        var rows = [];
                for(j=0; j<n; j++) {
                    rows[j] = "*";
                }

                cols[k] = rows;
                var rand = listofnumbers[Math.floor(Math.random()*listofnumbers.length)]; // random digit from listofnumbers array
                cols[k][rand-1] = rand;
            }

将数组推入数组

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