我正在尝试使用javascript从json文件中提取中位数

Question

尝试从各个年龄段中提取平均值并处理其中一个年龄段的缺失值。

var data={"users":[
{
"first_name":"Mikey",
"last_name":"Mouse",
"age": 24
},
{
"first_name":"Donald",
"lastName":"Duck",
"age": 29
},
{
"first_name":"Woody",
"lastName":"Woodpecker",
"age":
},
{
"first_name":"Bugs",
"lastName":"Bunny",
"age": 32
}  
]}

Answer 1

使用Ramda ，您可以执行以下操作（不知道您使用的是什么库，没有提供任何代码）：

const ages = R.compose(R.map(R.propOr(0, 'age')), R.propOr([], 'users'))
const mean = R.converge(R.divide, [R.sum, R.length])
const meanAges = R.compose(mean, ages)

console.log(meanAges(data)) // 21.25

如果未指定年龄，则R.propOr(0, 'age')年龄为0 。

 const data={"users":[ { "first_name":"Mikey", "last_name":"Mouse", "age": 24 }, { "first_name":"Donald", "lastName":"Duck", "age": 29 }, { "first_name":"Woody", "lastName":"Woodpecker" }, { "first_name":"Bugs", "lastName":"Bunny", "age": 32 } ]} const ages = R.compose(R.map(R.propOr(0, 'age')), R.propOr([], 'users')) const mean = R.converge(R.divide, [R.sum, R.length]) const meanAges = R.compose(mean, ages) console.log(meanAges(data)) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.22.1/ramda.min.js"></script> 

Answer 2

删除没有设定年龄的人，然后映射以仅获取年龄，然后排序并返回medean：

function getMedeanAge(data) {
    let ages = data
        .filter(cartoon => cartoon.age !== undefined)
        .map(cartoon => cartoon.age)
        .sort((a,b) => a > b);

    var middleIndex = ages.length / 2;

    return ages[Math.floor(middleIndex)] + ages[Math.ceil(middleIndex) / 2;
}

Answer 3

您可以对Array#forEach使用单循环方法，方法是收集所有值的sum和有效age的计数。 然后，可以将所有年龄段的总和除以count得到平均值。

 var data = { users: [{ first_name: "Mikey", last_name: "Mouse", age: 24 }, { first_name: "Donald", lastName: "Duck", age: 29 }, { first_name: "Woody", lastName: "Woodpecker", age: null }, { first_name: "Bugs", lastName: "Bunny", age: 32 }] }, sum = 0, count = 0, average; data.users.forEach(function (user) { if (typeof user.age === 'number') { sum += user.age; ++count; } }); average = sum / count; console.log(average);