JS 无法读取属性“长度"未定义的 [英] JS Cannot read property "length" of undefined

问题描述

我正在尝试使用给定的字符串创建一个对象，其中每个单词都有一个表示其长度的属性.

I'm trying to create an object using a given string where each word has a property stating its length.

var strings = {};

function findLongestWord(str) {
  var splitStr = str.split(" ");
    for (var i = 0; i <= str.length; i++){
     strings[splitStr[i]] = splitStr[i].length;
  }

  return strings;
}

findLongestWord("The quick brown fox jumped over the lazy dog");

我最终得到:

"TypeError": Cannot read property "length" of undefined.

如果我用 splitStr[0].length 替换 splitStr[i].length，代码运行正常，但当然给我对象中每个单词的相同数字.

If I were to replace splitStr[i].length with splitStr[0].length, the code runs properly, but of course giving me the same number for each word in the object.

感谢任何帮助，谢谢.

推荐答案

您正在循环错误的数组.你应该使用 i <splitStr.length.

you are looping over wrong array. you should use i < splitStr.length.

  var strings = {};    
  function findLongestWord(str) {
  var splitStr = str.split(" ");
    for (var i = 0; i < splitStr.length; i++){
     strings[splitStr[i]] = splitStr[i].length;
  }

  return strings;
}

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