一、js數組分組
1.js對數據分組類似group by
源碼如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>jquery 數組按某一字段分組</title>
<!-- <script src="./Scripts/jquery-3.3.1.min.js"></script> -->
<script src="./Scripts/jquery-1.10.2.min.js"></script>
</head>
<body>
<script type="text/javascript">
$(function()
{
let a = null;
let aa = a?a:0;
console.log(aa);
let b = undefined;
let bb = b?b:0;
console.log(bb);
let c = '';
let cc = c?c:0;
console.log(cc);
list = [
{"name": "John", "Average": 15, "High": 10, "DtmStamp": 1358226000000},
{"name": "Jane", "Average": 16, "High": 92, "DtmStamp": 1358226000000},
{"name": "Jane", "Average": 17, "High": 45, "DtmStamp": 1358226000000},
{"name": "John", "Average": 18, "High": 87, "DtmStamp": 1358226000000},
{"name": "Jane", "Average": 15, "High": 10, "DtmStamp": 1358226060000},
{"name": "John", "Average": 16, "High": 87, "DtmStamp": 1358226060000},
{"name": "John", "Average": 17, "High": 45, "DtmStamp": 1358226060000},
{"name": "Jane", "Average": 18, "High": 92, "DtmStamp": 1358226060000}
];
const sorted =groupBy(list, function (item) {
return [item.name];//按照name進行分組
});
console.log(sorted);
})
function groupBy(array, f)
{
debugger;
const groups = {};
array.forEach(function (o) { //注意這里必須是forEach 大寫
const group = JSON.stringify(f(o));
groups[group] = groups[group] || [];
groups[group].push(o);
});
return Object.keys(groups).map(function (group) {
return groups[group];
});
}
</script>
</body>
</html>
具體實現思路：
- 1.函數groupBy有兩個形參，一為對象數組，二為匿名函數（該函數功能：返回對象的某個指定屬性的屬性值並存放在數組中）；
- 2.groupBy函數內，先創建一個空對象；
- 3.然后forEach遍歷對象數組，遍歷時要執行的函數中只有一個形參o（數組中的每個元素）；
- 4.由於下面函數調用是想用name來分組，因此let group = JSON.stringify( f(o) )，相當於先獲取到對象數組list中的name屬性對應的屬性值並放入數組中：["John"]，然后再將屬性值轉換為json字符串：'["John"]'；
- 5.groups[group] = groups[group] || []，在js中對象也是關聯數組，因此這里相當於做了兩件事，一是把group作為groups的key，二是將對應的value初始化，第一次執行為空數組，循環執行時找到相同的name時保持不變；
- 6.groups[group].push( o )，這句相當於把list中每個對象壓入數組中作為value；
- 7.最后，Object.keys(groups)是取出groups對象中的所有key，然后遍歷一個個key組成的新數組，返回分好了組的二維數組
2.js根據json數據中的某一個屬性來給數據分組
源碼如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<span id ="span" style="width: 50px;height: 200px;"></span>
</body>
<script>
var arr = [{"Group":1,"Groupheader":"質量管理","Leftimg":"","Left":"","Min":"","Right":"","Rightimg":""},
{"Group":1,"Groupheader":"","Leftimg":"","Left":"","Min":"質量巡檢","Right":"","Rightimg":""},
{"Group":2,"Groupheader":"設備管理","Leftimg":"","Left":"","Min":"","Right":"","Rightimg":""},
{"Group":2,"Groupheader":"","Leftimg":"","Left":"","Min":"設備專業點檢","Right":"","Rightimg":""},
{"Group":2,"Groupheader":"","Leftimg":"","Left":"","Min":"設備日檢","Right":"","Rightimg":""},
{"Group":2,"Groupheader":"","Leftimg":"","Left":"","Min":"設備周檢","Right":"","Rightimg":""},
{"Group":2,"Groupheader":"","Leftimg":"","Left":"","Min":"設備月檢","Right":"","Rightimg":""}];
var map = {},
dest = [];
for(var i = 0; i < arr.length; i++){
var ai = arr[i];
if(!map[ai.Groupheader]){
dest.push({
Groupheader: ai.Groupheader,
data: [ai]
});
map[ai.Groupheader] = ai;
}else{
for(var j = 0; j < dest.length; j++){
var dj = dest[j];
if(dj.Groupheader == ai.Groupheader){
dj.data.push(ai);
break;
}
}
}
}
console.log(JSON.stringify(dest));
var sapn = document.getElementById("span");
span.innerHTML = JSON.stringify(dest);
</script>
</html>
二、js數組排序
參考1：https://blog.csdn.net/shuoSmallWhite/article/details/89447418
參考2：https://blog.csdn.net/qq_24607837/article/details/83342585
總結如下：
/**
* 數組排序：Desc:降序 Asc:升序
* @param {any} property
*/
function arraySort(property,type) {
return (firstobj, secondobj) => {
const firstValue = firstobj[property];
const secondValue = secondobj[property];
switch (type) {
case "Desc":
return secondValue - firstValue; //降序
case "Asc":
return firstValue - secondValue; //升序
default:
return firstValue - secondValue; //升序
}
};
}