Python JSON 到 CSV 转换

Question

我正在研究一个示例，但遇到了一些问题。我是python的初学者，并尝试提高自己。我正在尝试使用 openweather api 并从中获取一些数据，然后将这些数据写入 csv 文件。我的代码的目的是输入一个包含城市名称的 txt 文件，我想获取城市名称、国家代码、纬度、温度、风速、风向。然后将它们写入 csv 文件。我可以输入 txt 文件或通过命令行输入获取数据，但不能两者兼得。而且我想将数据写入 csv 文件。请你帮助我好吗？我可以将其写入控制台，但我需要将它们写入 csv 文件。但是，我无法将我的 json 对象转换为 csv

我的输入.txt

Los Angeles
San Francisco
...

我的代码：

import requests
from pprint import pprint
import csv
import pandas as pd

file = input("Input the filepath: ")

with open(file) as f:
    for line in f:
        line = line.strip()

        API_key = "MYAPIKEY"
        base_url = "http://api.openweathermap.org/data/2.5/weather?"
        headers = {'content-type': 'application/json'}

        city_name = line
       
        Final_url = base_url + "appid=" + API_key + "&q=" + city_name

        weather_data = requests.get(Final_url).json()

        print("\nCurrent Weather" + city_name + ":\n")
        weather_data = requests.get(Final_url, headers=headers)

        f = open('weather_data_file.csv', "w")
        f.write(weather_data.text)
        f.close()
        print(f)

编辑后的问题：

CSV 文件只包含最后一个城市数据，数据不在 如果我用 excel 打开，格式正确

它输出的数据：

{"coord":{"lon":-122.42,"lat":37.77},"weather":[{"id":802,"main":"Clouds","description":"scattered clouds","icon":"03d"}],"base":"stations","main":{"temp":284.74,"feels_like":280.59,"temp_min":283.15,"temp_max":286.48,"pressure":1024,"humidity":76},"visibility":10000,"wind":{"speed":5.1,"deg":260},"clouds":{"all":40},"dt":1609003065,"sys":{"type":1,"id":5817,"country":"US","sunrise":1608996226,"sunset":1609030632},"timezone":-28800,"id":5391959,"name":"San Francisco","cod":200}

Answer 1

要将您的 JSON 文件写入 CSV 文件：

import pandas as pd

if __name__ == "__main__":
    df = pd.read_json (r'ajsonfile.json')
    df.to_csv (r'filename.csv', index = None)

从 API 写入 JSON 数据：

# Get JSON Data
weather_data = requests.get(yourURL, headers=yourHeaders)

# Write to .CSV
f = open('weather_data_file.csv', "w")
f.write(weather_data.text)
f.close()

Answer 2

JavaScript Object Notation (JSON) 是数据的序列化表示。 pandas.read_json 尝试解码 JSON 并从中构建数据帧。在您使用requests 读取数据并使用.json() 调用将其反序列化为python 之后，它不再是JSON，pandas.read_json 将不起作用。

有时您可以直接从 python 对象构建数据框，但在这种情况下，您还有一个额外的问题。您一次只要求一行数据（一个城市），其信息嵌套在多个字典中。您可以使用 python 将接收到的城市数据扁平化为您想要的数据子集。而且由于您只是逐行工作，因此请使用csv 模块随时编写行。

解决办法是

import requests
from pprint import pprint
import csv

openweathermap_city_csv_header = ["City Name", "Country Code", "Lat", "Long", "Temperature",
    "Wind Speed", "Wind Direction"]

def openweathermap_city_flatten_record(record):
    coord = record["coord"]
    wind = record["wind"]
    return { "City Name":record["name"], 
        "Country Code":record["Code"],
        "Lat":coord["lat"],
        "Long":coord["lon"],
        "Temperature":record["main"]["temp"],
        "Wind Speed":wind["speed"],
        "Wind Direction":wind["deg"] }
    
file = input("Input the filepath: ")

with open(file) as cities, open('weather_data_file.csv', "w") as outfile:
    writer = csv.DictWriter(outfile, openweathermap_city_csv_header)
    for line in f:
        line = line.strip()
        API_key = "MYAPIKEY"
        base_url = "http://api.openweathermap.org/data/2.5/weather?"
        headers = {'content-type': 'application/json'}
        city_name = line
        Final_url = base_url + "appid=" + API_key + "&q=" + city_name
        weather_data = requests.get(Final_url, headers=headers).json()
        print("\nCurrent Weather" + city_name + ":\n")
        writer.writerow(openweathermap_city_flatten_record(weather_data))