javascript - 数据未正确分组

Question

我有包含国家名称的源数组和包含产品的其他数组。两个数组的索引相等。

array1:{China, China, Korea, USA, USA},

array2:{Lenovo, Asus, Samsung, Apple, Blackberry},

result : array : {{China, {Lenovo, Asus}}, {Korea, {Samsung}} ... }

但我不能正确地分组数组。我总能得到结果

{{China, {Lenovo}},{China, {Asus}} ... }.

我的代码是:

for (i = 0; i < XArray.length; i++) {
    var pointsArray = [];

    for (j = 0; j < XArray.length; j++) {

        if (XArray[i] == XArray[j]) {
            pointsArray.push([parseFloat(YArray[i]), parseFloat(ZArray[i])]);
        }
    }

    dataSource.push({
        name: i,
        data: pointsArray.slice()
    });
    pointsArray.length = 0;
}

Answer 1

我认为您应该使用一个对象来按国家/地区对制造商进行分组。像这样:

var conutries,
    manufacturers,
    i,
    len,
    country,
    manufacturerByCountry;
countries = ['China', 'China', 'Korea', 'USA', 'USA'];
manufacturers = ['Lenovo', 'Asus', 'Samsung', 'Apple', 'Blackberry'];
len = countries.length;
manufacturerByCountry = {};
// expected result:
// array : {'China': ['Lenovo', 'Asus'], 'Korea': ['Samsung'] ... }

for(i = 0; i < len; i++) {
    country = countries[i];
    if(!manufacturerByCountry[country]) {
        manufacturerByCountry[country] = [];
    }
    manufacturerByCountry[country].push(manufacturers[i]);
}

console.log(manufacturerByCountry);

DEMO

---

如果您仍然想获得您所描述的有问题的结果，那么您可以采用这样的解决方案:

var conutries,
    manufacturers,
    i,
    len,
    country,
    manufacturerByCountry,
    countryIndex,
    index;
countries = ['China', 'China', 'Korea', 'USA', 'USA'];
manufacturers = ['Lenovo', 'Asus', 'Samsung', 'Apple', 'Blackberry'];
len = countries.length,
manufacturerByCountry = [],
countryIndex = {};
// expected result:
// array : [[China, [Lenovo, Asus]], [Korea, [Samsung]] ... ]

for(i = 0; i < len; i++) {
    country = countries[i];
    if(countryIndex[country] === undefined) {
        index = manufacturerByCountry.push([country, []]) - 1;
        countryIndex[country] = index;
    } else {
        index = countryIndex[country];
    }
    manufacturerByCountry[index][1].push(manufacturers[i]);
}

console.log(manufacturerByCountry);

DEMO