Question

我有一个对象数组，它们是作为新类Card实例创建的，还有另一个我要在数组中找到索引并进行拼接的Card类实例：

...
this.cards.push(new Card(suit, rank));
>>>
        [
          Card { suit: 'Diamonds', rank: 'Jack' },
          Card { suit: 'Spades', rank: '3' },
          Card { suit: 'Spades', rank: 'Jack' },
          Card { suit: 'Diamonds', rank: 'Ace' },
          Card { suit: 'Clubs', rank: 'King' },
          Card { suit: 'Diamonds', rank: '6' },
          Card { suit: 'Spades', rank: '2' },
          Card { suit: 'Clubs', rank: '10' },
          Card { suit: 'Spades', rank: '7' },
          Card { suit: 'Clubs', rank: 'Queen' },
          Card { suit: 'Spades', rank: '10' }
        ]
    
const match = new Card('Clubs', rank: '10');
>>>     Card { suit: 'Clubs', rank: '10' }

在给定数组中搜索匹配项时，函数应返回索引7。 indexOf（）方法无法产生预期的结果。我怀疑我是在比较内存中的位置而不是值，但不知道如何解决此问题。

Answer 1

您只需编写自定义indexOf函数即可检查对象。

function myIndexOf(o) {    
    for (var i = 0; i < this.cards.length; i++) {
        if (this.cards[i].suit == o.suit && this.cards[i].rank == o.rank) {
            return i;
        }
    }
    return -1;
}

Answer 2

您的假设

我怀疑我是在比较内存中的位置而不是值

是正确的。 Array.prototype.findIndex是您的朋友在这里：

function compareCards(a,b) {
  return Object.keys(a).every(key => a[key] === b[key]) && Object.keys(b).every(key => b[key] === a[key]);
}

const arr = [{
    suit: 'Diamonds',
    rank: 'Jack'
  },
  {
    suit: 'Spades',
    rank: '3'
  },
  {
    suit: 'Spades',
    rank: 'Jack'
  },
  {
    suit: 'Diamonds',
    rank: 'Ace'
  },
  {
    suit: 'Clubs',
    rank: 'King'
  },
  {
    suit: 'Diamonds',
    rank: '6'
  },
  {
    suit: 'Spades',
    rank: '2'
  },
  {
    suit: 'Clubs',
    rank: '10'
  },
  {
    suit: 'Spades',
    rank: '7'
  },
  {
    suit: 'Clubs',
    rank: 'Queen'
  },
  {
    suit: 'Spades',
    rank: '10'
  }
];

const cardToFind = {
  suit: 'Clubs',
  rank: 'King'
};

let index = arr.findIndex(card => compareCards(card, cardToFind));

console.log(index);

Answer 3

您可以使用findIndex方法。它返回通过测试的数组中第一个元素的索引（作为函数提供）。

class Card {
  constructor(suit, rank) {
    this.suit = suit;
    this.rank = rank;
  }
}

let cards = [
  { suit: "Diamonds", rank: "Jack" },
  { suit: "Spades", rank: "3" },
  { suit: "Spades", rank: "Jack" },
  { suit: "Diamonds", rank: "Ace" },
  { suit: "Clubs", rank: "King" },
  { suit: "Diamonds", rank: "6" },
  { suit: "Spades", rank: "2" },
  { suit: "Clubs", rank: "10" },
  { suit: "Spades", rank: "7" },
  { suit: "Clubs", rank: "Queen" },
  { suit: "Spades", rank: "10" },
];

const match = (card, cards) => {
  return cards.findIndex((x) => x.suit === card.suit && x.rank === card.rank);
};

console.log(match(new Card("Clubs", "10"), cards));

有没有一种方法可以将类实例与该类实例数组中的元素进行比较？

3 个答案: