如何在javascript中划分多个数组

Posted 2023-03-14

【中文标题】如何在javascript中划分多个数组

【英文标题】：How to divide multi array in javascript

【发布时间】：2021-07-19 06:25:49

【问题描述】：

我有一个数组，每个索引中有 3 个数据 变量

var data = @json($data)

输出

(6) […, …, …, …, …, …]
0: day: "Saturday", totalIncome: 0, totalExpense: 300
1: day: "Sunday", totalIncome: 0, totalExpense: 0
2: day: "Monday", totalIncome: 0, totalExpense: 0
3: day: "Tuesday", totalIncome: 0, totalExpense: 0
4: day: "Wednesday", totalIncome: 500, totalExpense: 0
5: day: "Thursday", totalIncome: 0, totalExpense: 0
length: 6

我想做3个数组

var days = datas.day;
var incomes = datas.totalIncome;
var expenses = data.totalExpenses;

我现在应该怎么做才能从数据中创建这 3 个数组。请帮忙

【问题讨论】：

var data = @json($data) 看起来不像是有效的 JS？

对 laravel php 有效。 php数组到js数组的转换

那么 javascript 标签是干什么用的？

***.com/questions/33326699/…

您可以从中找到答案。谢谢

【参考方案1】：

在原版 JS 中可能是这样的：

const days = [], incomes = [], expenses = [];

for (let i = 0; i < data.length; i++) 
    days.push(data[i]["day"]);
    incomes.push(data[i]["totalIncome"]);
    expenses.push(data[i]["totalExpense"]);

【参考方案2】：

将您的数据映射到新数组中。

var days = datas.map(function(obj) 
    return obj['day'];
);
var incomes = datas.map(function(obj) 
    return obj['income'];
);
var expenses = datas.map(function(obj) 
    return obj['expenses'];
);

如果您安装了lodash。

var days = _.pluck(datas, 'day')

【参考方案3】：

使用原生的flatMap函数，例如：

    var groupBy = key => 
        return [
           day: "Saturday", totalIncome: 0, totalExpense: 300,
           day: "Sunday", totalIncome: 0, totalExpense: 0,
           day: "Monday", totalIncome: 0, totalExpense: 0,
           day: "Tuesday", totalIncome: 0, totalExpense: 0,
           day: "Wednesday", totalIncome: 500, totalExpense: 0,
           day: "Thursday", totalIncome: 0, totalExpense: 0
        ].flatMap(v => v[key])
    


    const days = groupBy('day')
    console.log(days)