计算 javascript 中的单词并将其推入对象

Question

我想实现一个 javascript 程序来计算一个单词和 return 这个单词及其出现的次数，例如 {hello : 2, "@hello":1, world : 1, toString:1}

下面是我的代码，但我只得到总字数

function words(str) { 
    app = {};
    return str.split(" ").length;
}

console.log(words("hello world"));

Answer 1

使用reduce迭代words数组，统计实例数：

function words(str) { 
    return str.split(" ").reduce(function(count, word) {
      count[word] = count.hasOwnProperty(word) ? count[word] + 1 : 1;
      
      return count;
    }, {});
}

console.log(words("reserved words like prototype and toString ok? Yes toString is fine"));

Answer 2

function words(str){


    var words = [];

    //check if words list is empty if so then insert the first word into the array


    if(!words.length){
        var word = str.split(" ")[0];
        words.push({"word":word, "occurences":1});
    }

    //convert string to array so you can iterate through it
    str = str.split(" ");

    //iterate through the array starting from the first position because word at the position 0 is already in the array
    for(var i = 1; i<str.length; i++){

        //iterate through the words list to the see if the word has appeared yet
        var wordExists = false;

        for(var j = 0; j<words.length; j++){
            if(str[i] == words[j].word){

                //word exists in word so count one up
                words[j].occurences += 1;

                //used to prevent the word from being inserted twice
                wordExists = true;
                break;
            }
        }

        //insert new word in words if it 
        if(!wordExists){
            words.push({"word":str[i], "occurences":1});
        }
    }
    return words;
}

Answer 3

这是我通过@ori传递的代码

function words(str) { 
    var adjustedStr = str.replace(/\n|\t|\s\s+/g, ' ');
    return adjustedStr.split(' ').reduce(function(count, word) {
    count[word] = (count[word] || 0) + 1;

    return count;
    }, {});
}

console.log(words("reserved words like prototype and toString ok?"));

它安慰了

{toString: "function toString() { [native code] }1"}

Answer 4

要在不使用 hasOwnerProperty 的情况下允许对象文字中的保留字，您可以为对象使用 null 构造函数。

例如

function words(str) { 
    var adjustedStr = str.replace(/\n|\t|\s\s+/g, ' ');
    return adjustedStr.split(' ').reduce(function(count, word) {
      count[word] = (count[word] || 0) + 1;
      return count;
    }, Object.create(null));
}

console.log(words("reserved words like prototype and toString ok?"));

Answer 5

一种 ES6 方法，它减少了一系列项目，例如字符串和 returns 计数：

const strFrequency = function (stringArr) {
  return stringArr.reduce((count, word) => {
        count[word] = (count[word] || 0) + 1;
        return count;
  }, {})
}

let names = ["Bob", "Bill", "Bo", "Ben", "Bob", "Brett", "Ben", "Bill", "Bo", "Ben", "Bob", "Ben"];

console.log(strFrequency(names));
// => {Bob: 3, Bill: 2, Bo: 2, Ben: 4, Brett: 1}

计算 javascript 中的单词并将其推入对象

Counting words in javascript and push it into an object

javascript

count

word