具有python中某些参数的json文件中的值总和

问题描述

我有这个python脚本，可以读取json文件，挑选出销量最高的汽车（完成这一部分），但是现在我需要弄清楚如何找到我们销量最高的年份（car_year） json文件示例，2002年共售出296辆汽车，而2007年arround则售出264辆汽车，我想出了如何对json文件的所有“ car_sales”进行求和，但我需要找出销量最高的年份

Python脚本：

#!/usr/bin/env python
import json
data = json.load(open('/home/ahmed/events.json'))
#finding the item with the highest sale 
event=max(data,key=lambda ev: ev['total_sales'])
print (event)
#sum the "car_sales" of all the items in the json file
count = sum(map(lambda x: int(x['total_sales']),data))
print (count)

这是json文件（一个测试）

[
     {
        "id": 47,"car": {
                "car_make": "Lamborghini","car_model": "Murciélago","car_year": 2002
        },"price": "$13724.05","total_sales": 149
},{
        "id": 48,"car": {
                "car_make": "volvo","car_model": "x20","car_year": 2010
        },"total_sales": 10
},{
        "id": 49,"car": {
                "car_make": "kia","car_model": "kia1.2","car_year": 2007
        },"total_sales": 114
},{
        "id": 50,"car": {
                "car_make": "renault","car_model": "p300","total_sales": 147
},{
        "id": 51,"car": {
                "car_make": "ferrari","car_model": "red","total_sales": 150
}
        ]

解决方法

• 使用import { Component,Input,OnInit } from '@angular/core'; @Component({ selector: 'app-rostericon',template: ` <i *ngIf="!layered" class="fa" [class]="iconClass" [style]="customStyle"></i> <span *ngIf="layered" className="fa-layers fa-fw"> <i class="fa" [class]="layer1"></i> <i class="fa" [class]="layer2" style="transform: shrink-6"></i> </span> `,styleUrls: ['./rostericon.component.scss'] }) export class RostericonComponent implements OnInit { @Input() icon:string; customStyle: any = {}; iconClass = ""; layer1 = ""; layer2 = ""; layered: boolean = false; constructor() { } ngOnInit(): void { switch (icon) { //example of how to handle the case case "copy": customStyle = { fontColor: red }; iconClass = "fa-copy"; break; case "reset": customStyle = { fontColor: red }; iconClass = "fa-undo-alt"; break; case "question": layered = true; layer1 = "fa-square"; layer2 = "fa-question"; break; case ... case ... case ... } } }
  • 使用pandas.DataFrame.sum获取多个列之一的总和
  • 使用Pandas: Boolean Indexing进行矢量化数据选择。
• 分解pandas
  • df['car.car_year'][df.total_sales == df.total_sales.max()]选择返回的所需列
    • 对所有列使用df['car.car_year']
  • df创建所有行的布尔值，其中[df.total_sales == df.total_sales.max()]与total_sales
  相同
• 使用pandas.DataFrame.groupby按特定列分组并汇总不同的计算，例如total_sales.max()和.sum

.max