I want to filter a JSON output but it gives me the following error:

File "main.py", line 40, in on_ready
output_dict = [x for x in a2 if x['type'] == 'ORDER_FILL']
File "main.py", line 40, in <listcomp>
output_dict = [x for x in a2 if x['type'] == 'ORDER_FILL']
TypeError: string indices must be integers

This is my code:

json_output = {'transactions': [{'id': '111', 'accountID': 'xxxxx', 'userID': xxxxx, 'batchID': '109', 'time': '2022-01-31T00:50:29.592777450Z', 'type': 'STOP_LOSS_ORDER', 'tradeID': '109', 'timeInForce': 'GTC', 'triggerCondition': 'DEFAULT', 'triggerMode': 'TOP_OF_BOOK', 'price': '15140.9', 'reason': 'ON_FILL'}, {'id': '112', 'accountID': 'xxxxx', 'userID': xxxxx, 'batchID': '112', 'requestID': '24908231217089037', 'time': '2022-01-31T08:29:58.903631976Z', 'type': 'MARKET_ORDER', 'instrument': 'DE30_EUR', 'units': '-0.1', 'timeInForce': 'FOK', 'positionFill': 'DEFAULT', 'reason': 'CLIENT_ORDER'}, {'id': '113', 'accountID': 'xxxxx', 'userID': xxxxx, 'batchID': '112', 'requestID': '24908231217089037', 'time': '2022-01-31T08:29:58.903631976Z', 'type': 'ORDER_FILL', 'orderID': '112', 'instrument': 'DE30_EUR', 'units': '-0.1', 'requestedUnits': '-0.1', 'price': '15499.6', 'pl': '5.9200', 'quotePL': '5.92', 'financing': '0.0000', 'baseFinancing': '0.00000000000000', 'commission': '0.0000', 'accountBalance': '525.0693', 'gainQuoteHomeConversionFactor': '1', 'lossQuoteHomeConversionFactor': '1', 'guaranteedExecutionFee': '0.0000', 'quoteGuaranteedExecutionFee': '0', 'halfSpreadCost': '0.0850', 'fullVWAP': '15499.6', 'reason': 'MARKET_ORDER', 'tradesClosed': [{'tradeID': '109', 'units': '-0.1', 'realizedPL': '5.9200', 'financing': '0.0000', 'baseFinancing': '0.00000000000000', 'price': '15499.6', 'guaranteedExecutionFee': '0.0000', 'quoteGuaranteedExecutionFee': '0', 'halfSpreadCost': '0.0850', 'plHomeConversionCost': '0.00', 'baseFinancingHomeConversionCost': '0.00000000000000', 'guaranteedExecutionFeeHomeConversionCost': '0', 'homeConversionCost': '0.00000000000000'}], 'fullPrice': {'closeoutBid': '15496.4', 'closeoutAsk': '15504.5', 'timestamp': '2022-01-31T08:29:58.871175423Z', 'bids': [{'price': '15499.6', 'liquidity': '100'}, {'price': '15499.1', 'liquidity': '100'}, {'price': '15496.4', 'liquidity': '100'}], 'asks': [{'price': '15501.3', 'liquidity': '100'}, {'price': '15501.9', 'liquidity': '100'}, {'price': '15504.5', 'liquidity': '100'}]}, 'homeConversionFactors': {'gainQuoteHome': {'factor': '1'}, 'lossQuoteHome': {'factor': '1'}, 'gainBaseHome': {'factor': '15422.8980'}, 'lossBaseHome': {'factor': '15577.9020'}}, 'plHomeConversionCost': '0.00', 'baseFinancingHomeConversionCost': '0.00000000000000', 'guaranteedExecutionFeeHomeConversionCost': '0', 'homeConversionCost': '0.00000000000000'}, {'id': '114', 'accountID': 'xxxxx', 'userID': xxxxx, 'batchID': '112', 'requestID': '24908231217089037', 'time': '2022-01-31T08:29:58.903631976Z', 'type': 'ORDER_CANCEL', 'orderID': '110', 'reason': 'LINKED_TRADE_CLOSED', 'closedTradeID': '109', 'tradeCloseTransactionID': '113'}, {'id': '115', 'accountID': 'xxxxx', 'userID': xxxxx, 'batchID': '112', 'requestID': '24908231217089037', 'time': '2022-01-31T08:29:58.903631976Z', 'type': 'ORDER_CANCEL', 'orderID': '111', 'reason': 'LINKED_TRADE_CLOSED', 'closedTradeID': '109', 'tradeCloseTransactionID': '113'}], 'lastTransactionID': '115'}
        
input_dict = json_output
output_dict = [x for x in input_dict if x['type'] == 'ORDER_FILL'] # Filter if type is this
output_json = json.dumps(output_dict)
print(output_json)

>Solution :

I will expand on RJ Adriaansen’s comment.

Your variable json_output is a dictionary. When iterating through dictionary, you are getting dictionary keys (in this case transaction and lastTransactionID).

What you want is to iterate through the list nested within transaction key in the root dictionary. You can do that like this:

[x for x in json_output['transactions'] if x['type'] == 'ORDER_FILL']