Python：从 JSON 中提取变量

Question

I would like to extract a number of variables from a JSON-reponse and save it in a csv-file. The JSON-reponse looks as follows:

{
"Response":"Success",
"Message":"Coin list succesfully returned!",
"BaseImageUrl":"https://www.cryptocompare.com",
"BaseLinkUrl":"https://www.cryptocompare.com",
"DefaultWatchlist":{
"CoinIs":"1182,7605,5038,24854,3807,3808,202330,5324,5031,178978",
"Sponsored":"1182"
},
"Data":{
"USC":{
"Id":"100954",
"Url":"/coins/usc/overview",
"ImageUrl":"/media/1383363/usc.png",
"Name":"USC",
"Symbol":"USC",
"CoinName":"Ultimate Secure Cash",
"FullName":"Ultimate Secure Cash (USC)",
"Algorithm":"SHA256",
"ProofType":"PoS",
"FullyPremined":"0",
"TotalCoinSupply":"200084200",
"PreMinedValue":"N/A",
"TotalCoinsFreeFloat":"N/A",
"SortOrder":"1233",
"Sponsored":false

I would like to get the following variables: Name, Symbol, CoinName and ID

In order to extract all the values of the JSON-response, I use the following code:

def getCoinList():
req = requests.get(‘https://www.cryptocompare.com/api/data/coinlist/’).json()   
info = req[‘Data’]
coinList = pd.DataFrame(info)
coinList = coinList.transpose()
coinList.to_csv(‘coinList.csv’)
return coinList

However, I would like to extract only the specified variables.

def getCoinList():
req = requests.get(‘https://www.cryptocompare.com/api/data/coinlist/’).json()['Data']
info = req['...'] /// How do I all four variables?
coinList = pd.DataFrame(info)
coinList = coinList.transpose()
coinList.to_csv(‘coinList.csv’)
return coinList

I am not sure how I can modify this code to extract only the four specified variables? Can anyone help me with this. Thanks in advance,

Answer 1

If you want a list containing several specific values in your dict , you need to manually create a list:

mylist = [req['Name'], req['Symbol'], req['CoinName'], req['ID']]

Or, if you want a dict :

mydict = {'Name': req['Name'], 'Symbol': req['Symbol'],
          'CoinName': req['CoinName'], 'ID': req['ID']}

So to write this to a csv:

import csv

with open('coinList.csv', 'a') as filep:
    csvwriter = csv.writer(filep)
    csvwriter.writerow([req['Name'], req['Symbol'], req['CoinName'], req['ID']])