编写一个函数，该函数返回它对应的所有键的所有值的数组[关闭]答案

【问题标题】：write a function that returns an array of all the values of all the keys it corresponds to [closed]编写一个函数，该函数返回它对应的所有键的所有值的数组[关闭]
【发布时间】：2016-11-08 12:00:36
【问题描述】：

我想创建一个函数，可以调用它来返回一个包含每个对象的所有值的数组。 e.g. function find ("firstName") returns ["Virginia", "Zadie", "Jane", "Bell"]

解释也很好，因为我对编程和尝试学习非常陌生。谢谢

var writers = [
  {
    firstName: "Virginia",
    lastName: "Woolf",
    occupation: "writer",
    age: 59,
    alive: false
  },
  {
    firstName: "Zadie",
    lastName: "Smith",
    occupation: "writer",
    age: 41,
    alive: true
  },
  {
    firstName: "Jane",
    lastName: "Austen",
    occupation: "writer",
    age: 41,
    alive: false
  },
  {
    firstName: "bell",
    lastName: "hooks",
    occupation: "writer",
    age: 64,
    alive: true
  },
];

【问题讨论】：

请说明您迄今为止尝试过的内容，包括代码示例。

标签： javascript arrays function object

【解决方案1】：

您可以使用map() 方法创建此函数。

var writers = [ { firstName: "Virginia", lastName: "Woolf", occupation: "writer", age: 59, alive: false }, { firstName: "Zadie", lastName: "Smith", occupation: "writer", age: 41, alive: true }, { firstName: "Jane", lastName: "Austen", occupation: "writer", age: 41, alive: false }, { firstName: "bell", lastName: "hooks", occupation: "writer", age: 64, alive: true }];

function get(key, arr) {
  return arr.map(function(e) {
    return e[key]
  })
}

console.log(get('firstName', writers))
console.log(get('occupation', writers))

【讨论】：

【解决方案2】：

您可以将密钥用作查找函数的参数。

property accessor，这里使用的是括号符号。

keys= 'name';
variable[key]

这等同于相同，写成点符号

variable.name

function find (key) {
    return writers.map(function (a) { 
        return a[key];
    });
}

var writers = [ { firstName: "Virginia", lastName: "Woolf", occupation: "writer", age: 59, alive: false }, { firstName: "Zadie", lastName: "Smith", occupation: "writer", age: 41, alive: true }, { firstName: "Jane", lastName: "Austen", occupation: "writer", age: 41, alive: false }, { firstName: "bell", lastName: "hooks", occupation: "writer", age: 64, alive: true }, ];
               
console.log(find('firstName'));
console.log(find('lastName'));

【讨论】：