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从对象数据中创建单独的数组并将它们存储到另一个数组中

javascript
7

假设我有一个空数组：

var list = [];

以下是问题：如果我有一个包含6个对象的 data 数组，这些对象如下所示：

var data = [];

data[0] = { Name: "Jack", accuracy: "average", accent: 79, weight: 1 };
data[1] = { Name: "Sara", accuracy: "good", accent: 24, weight: 2 };
data[2] = { Name: "Nick", accuracy: "not bad", accent: 89, weight: 1 };
data[3] = { Name: "Doe", accuracy: "good", accent: 88, weight: 4 };
data[4] = { Name: "Lee", accuracy: "excellent", accent: 63, weight: 9 };
data[5] = { Name: "Sasha", accuracy: "good", accent: 42, weight: 5 };

我该如何将list数组填充为这样的data数组中的数据：
var list = [
  ["Jack", "Sara", "Nick", "Doe", "Lee", "Sasha"],
  ["average", "good", "not bad", "good", "excellent", "good"]
];

我尝试使用这个for循环，但没有成功：

for ( var i=0; i < data.length; i++ ) {
 list[0].push( data[i].Name );
 list[1].push( data[i].accuracy);
}
console.log(list);


var data = [];

data[0] = {
  Name: "Jack",
  accuracy: "average",
  accent: 79,
  weight: 1
};
data[1] = {
  Name: "Sara",
  accuracy: "good",
  accent: 24,
  weight: 2
};
data[2] = {
  Name: "Nick",
  accuracy: "not bad",
  accent: 89,
  weight: 1
};
data[3] = {
  Name: "Doe",
  accuracy: "good",
  accent: 88,
  weight: 4
};
data[4] = {
  Name: "Lee",
  accuracy: "excellent",
  accent: 63,
  weight: 9
};
data[5] = {
  Name: "Sasha",
  accuracy: "good",
  accent: 42,
  weight: 5
};

for (var i = 0; i < data.length; i++) {
  list[0].push(data[i].Name);
  list[1].push(data[i].accuracy);
}
console.log(list);

10个回答
9

只需使用Array.prototype.map即可。该方法旨在从现有数组创建一个新数组，新数组的长度与原始数组完全相同：

const data = [{ Name: "Jack", accuracy: "average", accent: 79, weight: 1 },{ Name: "Sara", accuracy: "good", accent: 24, weight: 2 },{ Name: "Nick", accuracy: "not bad", accent: 89, weight: 1 },{ Name: "Doe", accuracy: "good", accent: 88, weight: 4 },{ Name: "Lee", accuracy: "excellent", accent: 63, weight: 9 },{ Name: "Sasha", accuracy: "good", accent: 42, weight: 5 }]

const list = [data.map(x=>x.Name), data.map(x=>x.accuracy)];

console.log(list);

2

将list的声明更改为包括您想要推送到的子数组。

然后您的代码就可以正常工作了。


注：Original Answer翻译成“最初的回答”。 

var list = [[],[]];


var data = [];

data[0] = { Name: "Jack", accuracy: "average", accent: 79, weight: 1 };
data[1] = { Name: "Sara", accuracy: "good", accent: 24, weight: 2 };
data[2] = { Name: "Nick", accuracy: "not bad", accent: 89, weight: 1 };
data[3] = { Name: "Doe", accuracy: "good", accent: 88, weight: 4 };
data[4] = { Name: "Lee", accuracy: "excellent", accent: 63, weight: 9 };
data[5] = { Name: "Sasha", accuracy: "good", accent: 42, weight: 5 };

for ( var i=0; i < data.length; i++ ) {
 list[0].push( data[i].Name );
 list[1].push( data[i].accuracy);
}
console.log(list);

1
它将抛出一个错误，因为你的列表数组是空的，没有任何数组可以推入值。
像这样初始化列表数组：
var list = [
  [],
  []
];

请看完整代码： 

var data = [];

data[0] = { Name: "Jack", accuracy: "average", accent: 79, weight: 1 };
data[1] = { Name: "Sara", accuracy: "good", accent: 24, weight: 2 };
data[2] = { Name: "Nick", accuracy: "not bad", accent: 89, weight: 1 };
data[3] = { Name: "Doe", accuracy: "good", accent: 88, weight: 4 };
data[4] = { Name: "Lee", accuracy: "excellent", accent: 63, weight: 9 };
data[5] = { Name: "Sasha", accuracy: "good", accent: 42, weight: 5 };

var list = [
  [],
  []
];

for ( var i=0; i < data.length; i++ ) {
 list[0].push( data[i].Name );
 list[1].push( data[i].accuracy);
}

console.log(list);

1
data.reduce((acc, r) => ([[...acc[0], r.name], [...acc[1], r.accuracy]]), [[], []])
1
虽然答案总是受欢迎的，但更好的做法是解释你的代码做了什么以及它如何帮助解决问题。请花点时间阅读《如何撰写一个好的答案？》（https://stackoverflow.com/help/how-to-answer）。 - Michael Dodd
1

试试这个

const list = [];
const names= data.map(d=>d.Name);
list.push(names);
const val = data.map(d=>d.accuracy);
list.push(val);
1
尝试使用 map 操作符：
list.push(data.map(n => n.Name), data.map(n => n.accuracy));
console.log(list);
扩展运算符在这里有什么用处？为什么要使用 new Array(...)，而 map() 已经返回了一个数组？ - connexo
1
你可以使用类似以下的 for 循环来完成它： 

var data = [];

data[0] = {
  Name: "Jack",
  accuracy: "average",
  accent: 79,
  weight: 1
};
data[1] = {
  Name: "Sara",
  accuracy: "good",
  accent: 24,
  weight: 2
};
data[2] = {
  Name: "Nick",
  accuracy: "not bad",
  accent: 89,
  weight: 1
};
data[3] = {
  Name: "Doe",
  accuracy: "good",
  accent: 88,
  weight: 4
};
data[4] = {
  Name: "Lee",
  accuracy: "excellent",
  accent: 63,
  weight: 9
};
data[5] = {
  Name: "Sasha",
  accuracy: "good",
  accent: 42,
  weight: 5
};

var list = [[],[]];

for (var i = 0; i < data.length; i++) {
  list[0].push(data[i].Name);
  list[1].push(data[i].accuracy);
}
console.log(list);

个人而言，我会使用map： 

var data = [];

data[0] = {
  Name: "Jack",
  accuracy: "average",
  accent: 79,
  weight: 1
};
data[1] = {
  Name: "Sara",
  accuracy: "good",
  accent: 24,
  weight: 2
};
data[2] = {
  Name: "Nick",
  accuracy: "not bad",
  accent: 89,
  weight: 1
};
data[3] = {
  Name: "Doe",
  accuracy: "good",
  accent: 88,
  weight: 4
};
data[4] = {
  Name: "Lee",
  accuracy: "excellent",
  accent: 63,
  weight: 9
};
data[5] = {
  Name: "Sasha",
  accuracy: "good",
  accent: 42,
  weight: 5
};

const names = data.map(item => item.Name)
const accuracies = data.map(item => item.accuracy)
const list = [names, accuracies]
console.log(list);

1
尝试使用 reduce 函数： 

 
var data = [];

data[0] = { Name: "Jack", accuracy: "average", accent: 79, weight: 1 };
data[1] = { Name: "Sara", accuracy: "good", accent: 24, weight: 2 };
data[2] = { Name: "Nick", accuracy: "not bad", accent: 89, weight: 1 };
data[3] = { Name: "Doe", accuracy: "good", accent: 88, weight: 4 };
data[4] = { Name: "Lee", accuracy: "excellent", accent: 63, weight: 9 };
data[5] = { Name: "Sasha", accuracy: "good", accent: 42, weight: 5 };

const list = data.reduce((acc,ele)=>{
 acc[0].push(ele.Name);
 acc[1].push(ele.accuracy);
 return acc
}, [[], []])

console.log(list);

1
这是一个涉及编程的示例，使用了 reduce ：

var data = [];

data[0] = { Name: "Jack", accuracy: "average", accent: 79, weight: 1 };
data[1] = { Name: "Sara", accuracy: "good", accent: 24, weight: 2 };
data[2] = { Name: "Nick", accuracy: "not bad", accent: 89, weight: 1 };
data[3] = { Name: "Doe", accuracy: "good", accent: 88, weight: 4 };
data[4] = { Name: "Lee", accuracy: "excellent", accent: 63, weight: 9 };
data[5] = { Name: "Sasha", accuracy: "good", accent: 42, weight: 5 };

console.log(data.reduce((p,c) => p[0].push(c.Name) && p[1].push(c.accuracy) && p,[[],[]]))

0
请看下面的代码；在您的初始代码中，您试图使用var list = [];，但由于数组未初始化，因此不会得到填充并将返回undefined; 

var data = [];

data[0] = {
  Name: "Jack",
  accuracy: "average",
  accent: 79,
  weight: 1
};
data[1] = {
  Name: "Sara",
  accuracy: "good",
  accent: 24,
  weight: 2
};
data[2] = {
  Name: "Nick",
  accuracy: "not bad",
  accent: 89,
  weight: 1
};
data[3] = {
  Name: "Doe",
  accuracy: "good",
  accent: 88,
  weight: 4
};
data[4] = {
  Name: "Lee",
  accuracy: "excellent",
  accent: 63,
  weight: 9
};
data[5] = {
  Name: "Sasha",
  accuracy: "good",
  accent: 42,
  weight: 5
};

// initialize the empty array(s) since it will get error when null / undefined;
var list = [ [], [] ];


for (var i = 0; i < data.length; i++) {
  list[0].push(data[i].Name);
  list[1].push(data[i].accuracy);
}

console.log(list);

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