数据结构
网络
RDBMS
操作系统
Java
MS Excel
iOS
HTML
CSS
Android
Python
C 编程
C++
C#
MongoDB
MySQL
Javascript
PHP
物理
化学
生物
数学
英语
经济
心理学
社会研究
时尚研究
法律研究根据多个筛选条件从 JSON 数据中计算平均值 JavaScript
假设我们有一个这样的对象数组 −
const arr = [
{ "SupplierName" : "John", "Category " : "A", "Points" : 3 },
{ "SupplierName" : "John", "Category " : "A", "Points" : 11 },
{ "SupplierName" : "John", "Category " : "A", "Points" : undefined },
{ "SupplierName" : "John", "Category " : "B", "Points" : 2 },
{ "SupplierName" : "John", "Category " : "B", "Points" : 6 },
{ "SupplierName" : "Praveen", "Category " : "A", "Points" : 3 },
{ "SupplierName" : "Praveen", "Category " : "A", "Points" : 7 }
];我们需要编写一个接收此类数组的 JavaScript 函数。
该函数应执行以下操作 −
- 将重复的供应商分组到一个唯一独立的对象中（重复指的是“SupplierName”和“Category”字段相同的对象）。
- 将它们的积分加在一起
- 向每个对象添加一个新的“平均值”字段，其中包含该供应商的平均积分。
因此，最终输出应如下所示 −
const output = [
{ "SupplierName" : "John", "Category " : "A", "Points" : 14, "Average" : 7 },
{ "SupplierName" : "John", "Category " : "B", "Points" : 8, "Average" : 4 },
{ "SupplierName" : "Praveen", "Category " : "A", "Points" : 10, "Average" : 5 }
];示例
const arr = [
{ "SupplierName" : "John", "Category " : "A", "Points" : 3 },
{ "SupplierName" : "John", "Category " : "A", "Points" : 11 },
{ "SupplierName" : "John", "Category " : "A", "Points" : undefined },
{ "SupplierName" : "John", "Category " : "B", "Points" : 2 },
{ "SupplierName" : "John", "Category " : "B", "Points" : 6 },
{ "SupplierName" : "Praveen", "Category " : "A", "Points" : 3 },
{ "SupplierName" : "Praveen", "Category " : "A", "Points" : 7 }
];
const groupAndAverage = (arr = []) => {
const groups = arr.reduce((acc, obj) => {
const name = obj.SupplierName + obj.Category;
if (acc[name]) {
if (obj.Points) (acc[name].Points += obj.Points) && ++acc[name].Average;
}
else { acc[name] = obj;
acc[name].Average = 1;
// taking 'Average' attribute as an items counter(on the first phase)
};
return acc;
}, {});
// getting "average of Points" const res = Object.keys(groups).map( name => { groups[name].Average = Math.round(groups[name].Points/groups[name].Average);
return groups[name];
});
return res;
}; console.log(JSON.stringify(groupAndAverage(arr), undefined, 4));输出
并且控制台中的输出将为 −
[
{
"SupplierName": "John",
"Category ": "A",
"Points": 22,
"Average": 6
},
{
"SupplierName": "Praveen",
"Category ": "A",
"Points": 10,
"Average": 5
}
]
更新于： 23-11-2020
1 千+ 浏览
广告