求助：无法在JavaScript二维数组中存储字符的问题

你给二维数组赋值字符的操作是成功的，问题出在console.log的输出代码里的一元加号运算符上。

问题原因 #

看你的console.log语句，比如" ", + gameBoard[0][0]这里的+是一元加号，作用是把后面的变量强制转换成数字类型。当你把gameBoard[1][1]设为字符串"a"后，+ gameBoard[1][1]会尝试将字符串"a"转换为数字，结果得到NaN（非数字值），所以输出时看起来像是没存储成功，但实际上数组里的"a"已经正常存进去了。

解决方法 #

去掉所有console.log里的一元加号，修改后的代码如下：

let gameBoard = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
];

console.log(" ", gameBoard[0][0] + " |", gameBoard[0][1] + " | " + gameBoard[0][2]);
console.log(" ", gameBoard[1][0] + " |", gameBoard[1][1] + " | " + gameBoard[1][2]);
console.log(" ", gameBoard[2][0] + " |", gameBoard[2][1] + " | " + gameBoard[2][2]);

gameBoard[1][1] = "a";

console.log(" ", gameBoard[0][0] + " |", gameBoard[0][1] + " | " + gameBoard[0][2]);
console.log(" ", gameBoard[1][0] + " |", gameBoard[1][1] + " | " + gameBoard[1][2]);
console.log(" ", gameBoard[2][0] + " |", gameBoard[2][1] + " | " + gameBoard[2][2]);

运行修改后的代码，第二次输出时中间位置会正常显示"a"，验证赋值操作成功。

内容的提问来源于stack exchange，提问作者mr.Hritik