从对象数组中返回名称数组

Question

我知道如何遍历一个对象并打印出我想要的一组值，但是我无法按照我想要的顺序打印它。**问题是： **给定一组游戏结果记录，通过返回一组玩家姓名来确定所有玩家是谁。该数组应按遇到名称的方式排序。示例输入：[  { winner: 'Alishah', loser: 'Bob',    loser_points: 3 },  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 1 },  { winner: 'Elise',   loser: 'Bob',    loser_points: 2 },  { winner: 'Elise',   loser: 'Maria',  loser_points: 4 },  { winner: 'Alishah', loser: 'Maria',  loser_points: 2 },  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 3 },  { winner: 'Xu Jin',  loser: 'Elise',  loser_points: 2 }]预期结果：['Alishah'，'Bob'，'Maria'，'徐进'，'Elise']**我到目前为止的代码：**let data = [  { winner: 'Alishah', loser: 'Bob',    loser_points: 3 },  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 1 },  { winner: 'Elise',   loser: 'Bob',    loser_points: 2 },  { winner: 'Elise',   loser: 'Maria',  loser_points: 4 },  { winner: 'Alishah', loser: 'Maria',  loser_points: 2 },  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 3 },  { winner: 'Xu Jin',  loser: 'Elise',  loser_points: 2 }];   console.log(main(data));

Answer 1

您可以为此使用.flatMap()和：Set()

let data = [

  { winner: 'Alishah', loser: 'Bob',    loser_points: 3 },

  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 1 },

  { winner: 'Elise',   loser: 'Bob',    loser_points: 2 },

  { winner: 'Elise',   loser: 'Maria',  loser_points: 4 },

  { winner: 'Alishah', loser: 'Maria',  loser_points: 2 },

  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 3 },

  { winner: 'Xu Jin',  loser: 'Elise',  loser_points: 2 }

];

const res = [...new Set(data.flatMap(x=>[x.winner, x.loser]))]

console.log( res )

解释：

• 使用.flatMap()方法我们将首先得到一个数组数组。这里的内部数组将是winner&loser名称的数组。

• 然后我们将展平数组以获得所有玩家姓名的单个数组。

• 最后使用[...new Set(array)]我们将在数组中获得不同的名称以实现所需的结果。

Answer 2

您可以使用Array.reduce()andSet来获取名称并删除重复项

Array.reduce()遍历数组。所以你可以将所有winner的 s 和losers 推送到初始的空数组中。

然后你可以创建一个新的Set. 这样，您可以删除重复项（因为所有项目都是string）。之后，您可以使用以下命令将其转换回数组spread syntax：[...new Set(array)]

const arr = [

  { winner: 'Alishah', loser: 'Bob',    loser_points: 3 },

  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 1 },

  { winner: 'Elise',   loser: 'Bob',    loser_points: 2 },

  { winner: 'Elise',   loser: 'Maria',  loser_points: 4 },

  { winner: 'Alishah', loser: 'Maria',  loser_points: 2 },

  { winner: 'Maria',   loser: 'Xu Jin', loser_points: 3 },

  { winner: 'Xu Jin',  loser: 'Elise',  loser_points: 2 }

]

const names = [...new Set(arr.reduce((acc, cur) => [...acc, cur.winner, cur.loser], []))]

console.log(names)

Answer 3

var players = collection.reduce((acc, player) => {

    if(!acc.inStore[player.winner]) {

        acc.players.push(player.winner)

        acc.inStore[player.winner] = true

    }

    if(!acc.inStore[player.loser]) {

        acc.players.push(player.loser)

        acc.inStore[player.loser] = true

    }

    return acc;

}, {players: [], inStore: {}}).players

// ["Alishah", "Bob", "Maria", "Xu Jin", "Elise"]