如何用python保存数据（Pandas）

Question

当我将数据保存到csv文件时，只保存id为103的记录，而id为101和102的记录不可用。你知道吗

import pandas as pd
import requests as rq

for vehicleList in range(101, 103):
    vehicleList = vehicleList + 1
    x = str(vehicleList)

    r = rq.get('https://api.tfl.gov.uk/vehicle/' + x + '/arrivals')
    r = r.text
    df = pd.read_json(r)

    df.to_csv('filename.csv')

Answer 1

保存前需要连接数据。例如：

import pandas as pd
import requests as rq

temp = pd.DataFrame()
df = pd.DataFrame()

for vehicleList in range(101, 103):
    vehicleList = vehicleList + 1
    x = str(vehicleList)
    r = rq.get('https://api.tfl.gov.uk/vehicle/' + x + '/arrivals')
    r = r.text
    temp = pd.read_json(r)

    # some identifier here  
    temp['Type'] = x

    # concat
    df = pd.concat([df, temp]).reset_index(drop=True)

df.to_csv('filename.csv')

将每个循环temp分配给一个临时数据帧，然后添加一个唯一的id来表示组temp['Type']，然后连接到df。循环完成后，保存包含所有迭代的df。你知道吗