如何从此JSON响应中获取特定部分？

Question

This is the code I have been using:

def get_api(url):
    #Funtion to ask and output the price
    x = urlopen( url )
    info = json.loads(x.read())
    x.close()

    avg24 = info["24h_avg"]

    gbp_volume = info["volume_percent"]

    last = info["last"]

    print avg24
    print gbp_volume
    print last

def max(url):
    g = urlopen( url )
    max_info = json.loads(g.read())
    g.close()

    maxcoin = max_info

    pprint(maxcoin)

get_api("https://api.bitcoinaverage.com/ticker/global/GBP/")
max("https://www.cryptonator.com/api/ticker/max-btc")

This outputs:

237.47
1.5
233.6
{u'error': u'',
 u'success': True,
 u'ticker': {u'base': u'MAX',
         u'change': u'0.00000062',
         u'price': u'0.00002303',
         u'target': u'BTC',
         u'volume': u'466841.69495860'},
 u'timestamp': 1417038842}

I would like to know how to only print the price or the volume for the second API response, since I can't do it the same way I did in the first function, ie:

avg24 = info["24h_avg"]

Answer 1

You can go multiple levels deep in a dictionary. So to get price from the maxcoin dictionary, simply do:

maxcoin_price = maxcoin['ticker']['price']

Answer 2

What the server is returning you can be understood (if it helps) as a "text-formatted" python dictionary (see type dict documentation )

So you have to load that Json text into a dict, and then you can easily refence items in it.

Hopefully running this will help you see how it works:

#!/usr/bin/env python

import json
import pprint

json_resp = ('{"ticker":{"base":"MAX","target":"BTC","price":"0.00002255",'
             '"volume":"465146.31939802","change":"-0.00000001"},'
             '"timestamp":1417040433,"success":true,"error":""}')
print json_resp    
json_dict = json.loads(json_resp)
print "Loaded a %s containing %s" % (type(json_dict), pprint.pformat(json_dict))
print "The ticker is a %s containing: %s"  % (
                type(json_dict['ticker']),
                pprint.pformat(json_dict['ticker'])
)
print "Price: %s" % json_dict['ticker']['price']
print "Volume: %s" % json_dict['ticker']['volume']

Which outputs:

{"ticker":{"base":"MAX","target":"BTC","price":"0.00002255","volume":"465146.31939802","change":"-0.00000001"},"timestamp":1417040433,"success":true,"error":""}
Loaded a {u'timestamp': 1417040433, u'ticker': {u'volume': u'465146.31939802', u'price': u'0.00002255', u'base': u'MAX', u'target': u'BTC', u'change': u'-0.00000001'}, u'success': True, u'error': u''} containing {u'error': u'',
 u'success': True,
 u'ticker': {u'base': u'MAX',
             u'change': u'-0.00000001',
             u'price': u'0.00002255',
             u'target': u'BTC',                                                                                                                                                                                
             u'volume': u'465146.31939802'},                                                                                                                                                                   
 u'timestamp': 1417040433}                                                                                                                                                                                     
The ticker is a <type 'dict'> containing: {u'base': u'MAX',                                                                                                                                                    
 u'change': u'-0.00000001',                                                                                                                                                                                    
 u'price': u'0.00002255',                                                                                                                                                                                      
 u'target': u'BTC',                                                                                                                                                                                            
 u'volume': u'465146.31939802'}                                                                                                                                                                                
Price: 0.00002255                                                                                                                                                                                              
Volume: 465146.31939802