CODEWITHSUNDEEP
pythonjsonapipython-3.xurl
Itsko
Itsko

Reputation: 29

Fetch specific data from JSON

I already asked that question and read a lot of JSON extraction examples and still I cant handle with that JSON... :( I am trying to get only the 'addr_tag' data without anything else, I can get some other information easily but i dont know the right syntax to get the 'addr_tag'

Thanks! 

import json
from urllib.request import urlopen


js1 = urlopen("https://blockchain.info/address/1dice97ECuByXAvqXpaYzSaQuPVvrtmz6?format=json&limit=1").read().decode('utf8')
obj1 = json.loads(js1)

print (obj1['txs']) #I need to know the what to put here instead of 'txs'...

Thanks!

Upvotes: 1

Views: 195

Answers (1)

Padraic Cunningham
Padraic Cunningham

Reputation: 180401

It is deeply nested, txs is the outer key, the value for txs is a list which has a dict with the inputs whose values is also a list that contains a dict, inside that dict prev_out has a dict as a value that has the addr_tagkey:

print(obj1["txs"][0]["inputs"][0]["prev_out"]["addr_tag"])

There are actually 2 addr_tags in the json the second is under:

print(obj1["txs"][0]["out"][1]["addr_tag"])

Satoshi Dice Change Address

If the keys are not always there you can use dict.get:

inter = js["txs"][0]
k1 = next((d["prev_out"].get("addr_tag") for d in inter["inputs"] if "prev_out" in d), None)
k2 = next((d.get("addr_tag") for d in inter["out"] if "addr_tag" in d), None)

If any key is not in your json, the value will be None so you can just check with an if: 

 if k1 is not None:
     .......
 if k2 is not None:
      ................

Looking at the link the data and format keeps changing from run to run, this function will recursively check all the dicts and pull any "addr_tag" values:

def rec_get(d, k):
    if isinstance(d, dict):
        if k in d:
            yield d[k]
        else:
            for v in d.values():
                yield from rec_get(v, k)
    elif isinstance(d, list):
        for v in d:
            yield from rec_get(v, k)


print(list(rec_get(js, "addr_tag")))

using the link json, you get which repeats some keys but you can call set(.. instead of list:

['Satoshi Dice Change Address', 'Satoshi Dice Change Address', 'SatoshiDICE 50%', 'Satoshi Dice Change Address']

Upvotes: 2

Related Questions