Question

我想了解如何正确创建一个物体数组哈希。

在这个例子中，我有一副牌（我省略了一些牌来缩短例子）：

var deckOfCards = [
  {color: "red", coat: "hearts", id: "Ace", faceValue: "A"},
  {color: "black", coat: "clubs", id: "Ace", faceValue: "A"},
  {color: "red", coat: "diamonds", id: "Ace", faceValue: "A"},
  {color: "black", coat: "spades", id: "Ace", faceValue: "A"},
  {color: "red", coat: "hearts", id: "Two", faceValue: "2"},
  {color: "black", coat: "clubs", id: "Two", faceValue: "2"},
  {color: "red", coat: "diamonds", id: "Two", faceValue: "2"},
  {color: "black", coat: "spades", id: "Two", faceValue: "2"},
  {color: "red", coat: "hearts", id: "Three", faceValue: "3"},
  {color: "black", coat: "clubs", id: "Three", faceValue: "3"},
  {color: "red", coat: "diamonds", id: "Three", faceValue: "3"},
  {color: "black", coat: "spades", id: "Three", faceValue: "3"},
  {color: "red", coat: "hearts", id: "Jack", faceValue: "J"},
  {color: "black", coat: "clubs", id: "Jack", faceValue: "J"},
  {color: "red", coat: "diamonds", id: "Jack", faceValue: "J"},
  {color: "black", coat: "spades", id: "Jack", faceValue: "J"},
  {color: "red", coat: "hearts", id: "Queen", faceValue: "Q"},
  {color: "black", coat: "clubs", id: "Queen", faceValue: "Q"},
  {color: "red", coat: "diamonds", id: "Queen", faceValue: "Q"},
  {color: "black", coat: "spades", id: "Queen", faceValue: "Q"},
  {color: "red", coat: "hearts", id: "King", faceValue: "K"},
  {color: "black", coat: "clubs", id: "King", faceValue: "K"},
  {color: "red", coat: "diamonds", id: "King", faceValue: "K"},
  {color: "black", coat: "spades", id: "King", faceValue: "K"}
];

我现在定义了我想要用于分组卡片的不同哈希......

var hashOfCardsByColor = [];
var hashOfCardsByCoat = [];
var hashOfCardsById = [];
var hashOfCardsByFaceValue = [];

当我遍历卡片组时，我想：

在尝试将卡放入哈希值之前检查哈希键是否存在，如果密钥不存在，则创建它。
将卡放入可以通过该密钥访问的卡阵列中。

我的代码......

  deckOfCards.forEach(function(d, i){
    // Handle coats...
    if (d.coat == "hearts") {
      // 1. If "hearts" key doesn't exist, create it and push card onto Array that it points to
      // 2. If "hearts" key does exist, just push card onto Array that it points to
    }
    else if (d.coat == "clubs") {
      // 1. If "clubs" key doesn't exist, create it and push card onto Array that it points to
      // 2. If "clubs" key does exist, just push card onto Array that it points to
    }
    else if (d.coat == "diamonds") {
      // 1. If "diamonds" key doesn't exist, create it and push card onto Array that it points to
      // 2. If "diamonds" key does exist, just push card onto Array that it points to
    }
    else (d.coat == "spades") {
      // 1. If "spades" key doesn't exist, create it and push card onto Array that it points to
      // 2. If "spades" key does exist, just push card onto Array that it points to
    }      
  });

我在上面每个细分受众群的主体中对第1步和第2步的语法和代码进行了挣扎，并感谢您提供的任何帮助。

此外，还有一个＆＃34;数组哈希＆＃34;正确的上述描述或者是＃34; Hashmap＆＃34;，例如？

Answer 1

好兄弟就这么简单。

  var hash = {};
    deckOfCards.forEach(function (e) {
        hash[e.coat] = hash[e.coat] || [];
        hash[e.coat].push(e);
    });

您的结果将会像

一样

object {hearts：Array [6]，clubs：Array [6]，diamond：Array [6]，spades：Array [6]}

只需复制粘贴n在控制台中查看。如果这个答案解决了你的问题必须投票并检查确定。

Answer 2

试试这个：

if(typeof hashOfCardsByColor[d.color] === 'undefined'){
    hashOfCardsByColor[d.color] = [];
}
hashOfCardsByColor[d.color].push(d);

Javascript：对象数组的散列（使用Deck of Cards示例）

2 个答案: