如何从字典列表中的字典中获取键和值

Question

I would like to get the values from a list within a dictionary. I get the following json data structure when I make an Oanda REST-API request.

When I use the get function I can access the dict and the keys and its values from "trades" and "lastTransactionID", but do not know how to get the list items which are in the "trades" key.

I would really appreciate if you could help me to get this running

Works print rv.get("trades")

Does not work print rv.get("trades").get("financing")

{
  "trades": [
    {
      "financing": "0.0000", 
      "openTime": "2017-11-08T17:21:49.533679739Z", 
      "price": "1.15901", 
      "unrealizedPL": "-0.0001", 
      "realizedPL": "0.0000", 
      "instrument": "EUR_USD", 
      "state": "OPEN", 
      "initialUnits": "1", 
      "currentUnits": "1", 
      "id": "2046"
    }, 
    {
      "financing": "0.0000", 
      "openTime": "2017-11-08T17:19:27.343697147Z", 
      "price": "1.15905", 
      "unrealizedPL": "-0.0001", 
      "realizedPL": "0.0000", 
      "instrument": "EUR_USD", 
      "state": "OPEN", 
      "initialUnits": "1", 
      "currentUnits": "1", 
      "id": "2044"
    }
  ], 
  "lastTransactionID": "2046"
}

Thanks for your help and kind regards

Answer 1

Just iterate over the list:

for trade in rv.get("trades"):
    print trade.get("financing")

print rv.get("trades").get("financing") doesn't work because rv.get("trades") returns a list of dictionaries. Those dictionaries are the ones with the "financing" key.

Answer 2

You just need to iterate over the list:

Demo here

 data = {
      "trades": [
        {
          "financing": "0.0000", 
          "openTime": "2017-11-08T17:21:49.533679739Z", 
          "price": "1.15901", 
          "unrealizedPL": "-0.0001", 
          "realizedPL": "0.0000", 
          "instrument": "EUR_USD", 
          "state": "OPEN", 
          "initialUnits": "1", 
          "currentUnits": "1", 
          "id": "2046"
        }, 
        {
          "financing": "0.0000", 
          "openTime": "2017-11-08T17:19:27.343697147Z", 
          "price": "1.15905", 
          "unrealizedPL": "-0.0001", 
          "realizedPL": "0.0000", 
          "instrument": "EUR_USD", 
          "state": "OPEN", 
          "initialUnits": "1", 
          "currentUnits": "1", 
          "id": "2044"
        }
      ], 
      "lastTransactionID": "2046"
    };

    for d in data['trades']:
        print(d['openTime'])

This returns:

2017-11-08T17:21:49.533679739Z
2017-11-08T17:19:27.343697147Z

Answer 3

rv.get("trades").get("financing") did not work because, trades value is not a dictionary but a list. You can check the type of it by doing type(rv.get('trades')) . So the correct way is

rv.get("trades")[0].get("financing")
rv.get("trades")[1].get("financing")

So you need to iterate over the list as

for item in rv.get('trades'):
    print(item.get('financing'))

Answer 4

Another neat alternative would be to use list comprehension, which will allow for a one-line solution:

[trade.get("financing") for trade in rv.get("trades")]

Note that this is not better than @Bahrom answer, just more pythonic in my opinion.