Question

在我的图表中，我有三种实体。省，地区和城市。

关系是城市属于地区，而地区属于省。

这是我的数据库表地区。

id | region_name      | region_parent_id
1  | Western province | null 
2  | Colombo          | 1
3  | Gampaha          | 1
4  | Kaluthara        | 1
5  | Nugegoda         | 2
6  | Maharagama       | 2
7  | Central province | null
8  | Kandy            | 7
9  | Mathale          | 7
10 | theldeniya       | 8
11 | penideniya       | 8

如果我推导出关系，我会是这样，

西部省份

科伦坡

  Nugegoda
  Maharagama

Gampaha

Kaluthara

中部省份

Kandy

Theldeniya
Penideniya

数学

我以这样的对象数组的形式获取这些数据，

const regions = [
{id:1,region_name:"Western province",region_parent_id:null},
{id:2,region_name:"Colombo",region_parent_id:1},
{id:3,region_name:"Gampaha",region_parent_id:1},
{id:4,region_name:"Kaluthara",region_parent_id:1},
{id:5,region_name:"Nugegoda",region_parent_id:2},
{id:6,region_name:"Maharagama",region_parent_id:2},
{id:7,region_name:"Central province",region_parent_id:null},
{id:8,region_name:"Kandy",region_parent_id:7},
{id:9,region_name:"Mathale",region_parent_id:7},
{id:10,region_name:"theldeniya",region_parent_id:8},
{id:11,region_name:"penideniya",region_parent_id:8}

]

console.log(regions.filter(e=> !e.region_parent_id ))

我可以很容易地得到像这样的省份。

console.log(regions.filter(e=> !e.region_parent_id ))

但是如何获取地区列表和城市列表？

任何帮助！

非常感谢！ =）

Answer 1

尝试一下：

var parId = prompt("Enter region parent id : " ) ;

const regions = [
  {id:1,region_name:"Western province",region_parent_id:null},
  {id:2,region_name:"Colombo",region_parent_id:1},
  {id:3,region_name:"Gampaha",region_parent_id:1},
  {id:4,region_name:"Kaluthara",region_parent_id:1},
  {id:5,region_name:"Nugegoda",region_parent_id:2},
  {id:6,region_name:"Maharagama",region_parent_id:2},
  {id:7,region_name:"Central province",region_parent_id:null},
  {id:8,region_name:"Kandy",region_parent_id:7},
  {id:9,region_name:"Mathale",region_parent_id:7},
  {id:10,region_name:"theldeniya",region_parent_id:8},
  {id:11,region_name:"penideniya",region_parent_id:8}
]

function belong(dis) {
  var getProvince = regions.find( e => e.id === dis ) ;
  if ( getProvince ) {
    console.log("==========" + getProvince.region_name + "==========" ) ;
    regions.map( c => {if (c.region_parent_id === dis ) console.log(c.region_name + " " + c.id +" Parent:(" + c.region_parent_id +")") } )
  }
}

belong( parseInt(parId) );

Answer 2

按以下方式使用过滤器，您将获得所需的结果。

const regions = [
  {id:1,region_name:"Western province",region_parent_id:null},
  {id:2,region_name:"Colombo",region_parent_id:1},
  {id:3,region_name:"Gampaha",region_parent_id:1},
  {id:4,region_name:"Kaluthara",region_parent_id:1},
  {id:5,region_name:"Nugegoda",region_parent_id:2},
  {id:6,region_name:"Maharagama",region_parent_id:2},
  {id:7,region_name:"Central province",region_parent_id:null},
  {id:8,region_name:"Kandy",region_parent_id:7},
  {id:9,region_name:"Mathale",region_parent_id:7},
  {id:10,region_name:"theldeniya",region_parent_id:8},
  {id:11,region_name:"penideniya",region_parent_id:8}
];

var province = regions.filter(e => !e.region_parent_id);

province.forEach(p => { 
  p.district = regions.filter(e => e.region_parent_id == p.id); 
  // Uncomment following snippet if you want to have cities list inside district object also.
  //p.district.forEach(d => { 
  //  d.city = regions.filter(e => e.region_parent_id == d.id);
  //});
  
  var districtIds = p.district.map(d => d.id);
  p.city = regions.filter(e => districtIds.includes(e.region_parent_id));
});

console.log(province);

Answer 3

尝试一下：

const regions = [
  { id: 1, region_name: "Western province", region_parent_id: null },
  { id: 2, region_name: "Colombo", region_parent_id: 1 },
  { id: 3, region_name: "Gampaha", region_parent_id: 1 },
  { id: 4, region_name: "Kaluthara", region_parent_id: 1 },
  { id: 5, region_name: "Nugegoda", region_parent_id: 2 },
  { id: 6, region_name: "Maharagama", region_parent_id: 2 },
  { id: 7, region_name: "Central province", region_parent_id: null },
  { id: 8, region_name: "Kandy", region_parent_id: 7 },
  { id: 9, region_name: "Mathale", region_parent_id: 7 },
  { id: 10, region_name: "theldeniya", region_parent_id: 8 },
  { id: 11, region_name: "penideniya", region_parent_id: 8 }
];

const provinces = regions.filter(region => !region.region_parent_id);
for (let i = 0; i < provinces.length; i++) {
  const currentProvince = provinces[i];
  // get districts for this now
  currentProvince.districts = regions.filter(region => region.region_parent_id === currentProvince.id);
  for (let j = 0; j < provinces[i].districts.length; j++) {
    const currentDistrict = provinces[i].districts[j];
    // get cities for the district
    currentDistrict.cities = regions.filter(region => region.region_parent_id === currentDistrict.id);
  }
}

console.log(provinces)

基于id的Javascript过滤器

3 个答案: