以下代码映射JSON文件，并显示唯一AREAID值的逗号列表，并将其显示在：
<p id="demog" style="border: 2px solid green;"></p>
我希望下面的代码在不破坏映射的情况下计算每个唯一值重复的次数。
结果应该看起来像中的内容
<p id="demob" style="border: 2px solid blue;"></p>
我假设它需要某种forEach循环，不确定如何做到这一点。
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var myObjjj = JSON.parse(this.responseText);
const mArrayE = myObjjj.features.filter(c => c.properties.PRUID === "48").map(res => ' of ' + res.properties.AREAID);
const marketE = Array.from(new Set(mArrayE)).sort();
document.getElementById("demog").innerHTML = marketE;
}
};
xmlhttp.open("GET", "https://api.npoint.io/d901ff317ae962d8c376", true);
xmlhttp.send();<!DOCTYPE html>
<html>
<head>
<title>Read data from External JSON file using JavaScript</title>
</head>
<body>
<h3>Unique Values and repetitions.</h3>
<p id="demog" style="border: 2px solid green;"></p>
<h3>Desired Result</h3>
<p id="demob" style="border: 2px solid blue;">3 of area1, 4 of area2, 5 of area3, 7 of area4, 2 of area5</p>
</body>
</html>Json来自URL-https://api.npoint.io/d901ff317ae962d8c376
{"type":"FeatureCollection","features":[
{"type":"Feature","properties":{"CDUID":"4811","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 11","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4807","COLOR":"#00fffc","PRUID":"48","AREAID":"area1","CDNAME":"Division No. 7","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4815","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 15","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4802","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 2","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4808","COLOR":"#00fffc","PRUID":"48","AREAID":"area1","CDNAME":"Division No. 8","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4803","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 3","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4801","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 1","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4804","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 4","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4801","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 1","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4804","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 4","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4806","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 6","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4816","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 16","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4812","COLOR":"#0600ff","PRUID":"48","AREAID":"area5","CDNAME":"Division No. 12","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4805","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 5","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4817","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 17","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4813","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 13","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4810","COLOR":"#0600ff","PRUID":"48","AREAID":"area5","CDNAME":"Division No. 10","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4819","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 19","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4818","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 18","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4814","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 14","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4809","COLOR":"#00fffc","PRUID":"48","AREAID":"area1","CDNAME":"Division No. 9","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}}]}
对我来说，这个api给出了一个错误，所以手动输入
let myObjjj = {"type":"FeatureCollection","features":[
{"type":"Feature","properties":{"CDUID":"4811","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 11","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4807","COLOR":"#00fffc","PRUID":"48","AREAID":"area1","CDNAME":"Division No. 7","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4815","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 15","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4802","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 2","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4808","COLOR":"#00fffc","PRUID":"48","AREAID":"area1","CDNAME":"Division No. 8","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4803","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 3","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4801","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 1","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4804","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 4","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4801","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 1","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4804","COLOR":"#ff0000","PRUID":"48","AREAID":"area3","CDNAME":"Division No. 4","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4806","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 6","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4816","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 16","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4812","COLOR":"#0600ff","PRUID":"48","AREAID":"area5","CDNAME":"Division No. 12","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4805","COLOR":"#fffc00","PRUID":"48","AREAID":"area2","CDNAME":"Division No. 5","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4817","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 17","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4813","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 13","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4810","COLOR":"#0600ff","PRUID":"48","AREAID":"area5","CDNAME":"Division No. 10","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4819","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 19","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4818","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 18","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4814","COLOR":"#ff00f0","PRUID":"48","AREAID":"area4","CDNAME":"Division No. 14","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}},
{"type":"Feature","properties":{"CDUID":"4809","COLOR":"#00fffc","PRUID":"48","AREAID":"area1","CDNAME":"Division No. 9","CDTYPE":"CDR","PRNAME":"Alberta","KML_STYLE":"area6"}}]}
let items = {}
myObjjj .features
.filter(c => c.properties.PRUID === "48")
.forEach(element => {
if (!items[element.properties.AREAID]) {
items[element.properties.AREAID] = 0
}
items[element.properties.AREAID]++
})
let html_item = ''
for (const key in items) {
html_item += `${items[key]} of ${key} <br> `
}
document.getElementById("demog").innerHTML = html_item;<!DOCTYPE html>
<html>
<head>
<title>Read data from External JSON file using JavaScript</title>
</head>
<body>
<h3>Unique Values and repetitions.</h3>
<p id="demog" style="border: 2px solid green;"></p>
<h3>Desired Result</h3>
<p id="demob" style="border: 2px solid blue;">3 of area1, 4 of area2, 5 of area3, 7 of area4, 2 of area5</p>
</body>
</html>