Question

我正在尝试从freeCodeCamp进行罗马数字挑战。我不知道为什么会出现以下错误：

if（numKey [i] [0] <=剩余）{ TypeError：无法读取未定义的属性“ 0”

这是我的代码：

function convertToRoman(num) {
 const numKey = [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50,'L'], [40, 'XL'],  [10, 'X'], [9, 'IX'] [5, 'V'], [4, 'IV'] [1, 'I']];
 let remaining = num;
 let romanStr = '';
 while(remaining > 0) {
      for(let i = 0; i < numKey.length; i++) {
            if(numKey[i][0] <= remaining) {
                  let j = 0;
                  while(j < Math.floor(remaining/numKey[i][0])) {
                        romanStr += numKey[i][1]
                        remaining -= numKey[i][0] * Math.floor(remaining/numKey[i][0])
                        j++
                  }
            }
      }
      break;
 }
 return romanStr;
}

我不知道为什么numKey[i][0]是不确定的。据我所知，它永远不会超出范围，当我在上一行中执行console.log(numKey[i][0])时，它始终会打印正确的值。有什么我想念的吗？

谢谢！

Answer 1

您的循环是正确的。但是数组错了，在最后两个数组中缺少一些export PATH=$PATH:/user/bin;/Applications/MiKTeX Console.app/Contents/bin/cjklatex

,无效

在以下代码段中检查此内容。查看其未定义的

[9, 'IX'] [5, 'V'], [4, 'IV'] [1, 'I']

const numKey = [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50,'L'], [40, 'XL'],  [10, 'X'], [9, 'IX'] [5, 'V'], [4, 'IV'] [1, 'I']];
console.log(numKey)

Answer 2

我认为您的代码中只有一个错字，numKey数组的格式不正确：

尝试：

function convertToRoman(num) {
 const numKey = [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50,'L'], [40, 'XL'],  [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I']];

 let remaining = num;
 let romanStr = '';
 while(remaining > 0) {
      for(let i = 0; i < numKey.length; i++) {
            if(numKey[i][0] <= remaining) {
                  let j = 0;
                  while(j < Math.floor(remaining/numKey[i][0])) {
                        romanStr += numKey[i][1]
                        remaining -= numKey[i][0] * Math.floor(remaining/numKey[i][0])
                        j++
                  }
            }
      }
      break;
 }
 return romanStr;
}

console.log(convertToRoman(133));
console.log(convertToRoman(42));

无法弄清楚为什么我得到“无法读取未定义的属性'0'”错误

2 个答案: