javascript对象属性的笛卡尔积

本文介绍了javascript对象属性的笛卡尔积的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有以下形式的对象（下面的简化测试用例）

I have an object of the following form (simplified test case below)

var test = { shirts: { sizes: ['large', 'medium'] ,colors:['red', 'blue'] } , trousers: { type: ['formal', 'casual'] , pattern: ['plaid', 'stripes'] } };

我想生成属性的笛卡尔积，以便输出是以下形式的数组：

I want to generate a cartesian product of the properties so that the output is an array of the following form:

// desired output [ {shirts:{sizes:'large', color:'red'}, trousers:{type:'formal', pattern:'plaid'}} ,{shirts:{sizes:'large', color:'red'}, trousers:{type:'formal', pattern:'stripes'}} ,{shirts:{sizes:'large', color:'red'}, trousers:{type:'casual', pattern:'plaid'}} , {shirts:{sizes:'large', color:'red'}, trousers:{type:'casual', pattern:'stripes'}} ,{shirts:{sizes:'large', color:'blue'}, trousers:{type:'formal', pattern:'plaid'}} ..... and so on ]

我怎样才能做到这一点？我编写了以下代码（基于对来自另一个SO帖子的数组的笛卡尔积的代码的修改）但我似乎将自己绑在试图使其工作的结。

How can I achieve this? I worked up the following code (based on a modification of code for cartesian product of array from another SO post) but I seem to be tying myself in knots trying to get this to work.

function myCartesianProduct(input, current) { if (!input) { return []; } var head = input[Object.keys(input)[0]]; var tail = objSlice(input); var output = []; for (var key in head) { for (var i = 0; i < head[key].length; i++) { var newCurrent = copy(current); newCurrent[key] = head[key][i]; if (Object.keys(tail).length) { //if tail.length var productOfTail = myCartesianProduct(tail, newCurrent); output = output.concat(productOfTail); } else { output.push(newCurrent); } } } return output; } function objSlice(obj) { var slicedObj = angular.copy(obj); // copy object using angularJs copy method delete slicedObj[Object.keys(slicedObj)[0]]; //delete the first key return slicedObj; }; function copy(obj) { var res = {}; for (var p in obj) res[p] = obj[p]; return res; } console.log(myCartesianProduct(test));

预先感谢您的帮助！

推荐答案

好的，让我们从一个生成给定数组产品的函数开始：

Ok, let's start with a function that generates a product of given arrays:

function product(args) { if(!args.length) return [[]]; var prod = product(args.slice(1)), r = []; args[0].forEach(function(x) { prod.forEach(function(p) { r.push([x].concat(p)); }); }); return r; }

下一个使用产品将 {a：[1,2]，b：[3,4]} 之类的内容转换为 [{a：1，b ：3}，{a：1，b：4}，{a：2，b：3}，{a：2，b：4}] ：

The next one uses product to convert something like {a:[1,2], b:[3,4]} into [{a:1,b:3},{a:1,b:4},{a:2,b:3},{a:2,b:4}]:

function objectProduct(obj) { var keys = Object.keys(obj), values = keys.map(function(x) { return obj[x] }); return product(values).map(function(p) { var e = {}; keys.forEach(function(k, n) { e[k] = p[n] }); return e; }); }

对于您的测试数据，您必须应用两次：

For your test data, you have to apply it twice:

var result = {}; Object.keys(test).forEach(function(k) { result[k] = objectProduct(test[k]) }); result = objectProduct(result);

这可以为您提供所需的输出。

This gives you the output you wanted.