如何在javascript中划分多个数组答案

【问题标题】：How to divide multi array in javascript如何在javascript中划分多个数组
【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？
stackoverflow.com/questions/33326699/…
您可以从中找到答案。谢谢

标签： javascript laravel

【解决方案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"]);
}

【讨论】：

【解决方案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')

【讨论】：

【解决方案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)

【讨论】：