js实现统计数组和对象数组中具有相同属性的个数【2021.11.11】_js判断数组对象中某个字段值一致的数量-优快云博客

本文链接：https://blog.youkuaiyun.com/masierty/article/details/121290123

这篇博客介绍了两种JavaScript方法来统计同一分数出现的次数。第一种方法通过创建数组并遍历，将成绩作为对象的属性，统计相同分数的频率。第二种方法利用数组的reduce方法，对包含学生对象的数组进行处理，按成绩分组，展示每个分数对应的多个学生对象。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

<!DOCTYPE html>
<html lang="en">

<head>
   <meta charset="UTF-8">
   <meta http-equiv="X-UA-Compatible" content="IE=edge">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>Document</title>
</head>

<body>

</body>
<script>
   //1班同一分数相同的人数
   //方法1建立数组，遍历给对象当属性名，如果相等的成绩，则值加1
   class oneClassStudent {
      constructor() {
         this.grade = parseInt(Math.random() * 100);
      }
   }
   let gradeAry = [];
   let myFun = function () {
      let obj = {};
      for (let i = 1; i < 33; i++) {
         let grades = new oneClassStudent;
         gradeAry.push(grades.grade);
      }
      console.log(gradeAry);
      for (let i = 0, k = gradeAry.length; i < k; i++) {//77,23,77
         let item = gradeAry[i];
         obj[item] = (obj[item] + 1) || 1;
      }
      return obj;
   }
   console.log(myFun());

   //1班同一分数相同的人数
   //方法2,如果我在数组里面放对象[{name:p,scor:2},{name:b,scor:32},{name:c,scor:12}]

   let TwoClassStudent = [{ name: "王二", scor: 12 }, { name: "李四", scor: 32 }, { name: "彭一", scor: 42 }, { name: "老六", scor: 12 }];
   let sameScore = function (objArray, property) {
      return objArray.reduce(function (new_obj, valve) {
         let key = valve[property];//当前的valve是数组对象里面的对象,property是索引
         if (!new_obj[key]) {
            new_obj[key] = [];
         }
         new_obj[key].push(valve);
         return new_obj;
      }, {});//初始值是个数组
   }
   let oneClass_score = sameScore(TwoClassStudent, 'scor');
   console.log(oneClass_score);
   // 12: Array[{ … }, { … }]

   // 0: Object { name: "王二", scor: 12 }

   // 1: Object { name: "老六", scor: 12 }

   // length: 2

   //    < prototype >: Array[]

   // 32: Array[{ … }]

   // 0: Object { name: "李四", scor: 32 }

   // length: 1

   //    < prototype >: Array[]

   // 42: Array[{ … }]

   // 0: Object { name: "彭一", scor: 42 }

   // length: 1

   // < prototype >: Array[]
</script>

</html>