从字典中读取时，我得到“int”对象没有属性“__getitem__”错误

Question

In one python file I store values in a dictionary eg:

 messageDict[ObservationRawDataId] = {'timestamp': TimeStamp, 'tanksystemid': TankSystemId,
                        'newDelivery': delivery,'oldDelivery':RawDeliveryLitres ,'grade' :ProductName,'sitecode':SiteCode}
 formMessageBody(messageDict)

In another python file I try to formulate a plain text messge from that dictionary;

def formMessageBody( messageDict) :
    try :
        print 'SiteCode', 'Date', 'Product', 'NewDelievry','OldDelivery'
        for tuple_a in messageDict.items():
            for dic_a in tuple_a:
                print tuple_a
                print dic_a['sitecode']
                print  dic_a['sitecode'], dic_a['timestamp'], dic_a['grade'],
                                                            dic_a['newDelivery'],dic_a['oldDelivery']
    except Exception as error:
        print format(error)

but I could not read value from the tuple. tuple_a prints as;

(14118912, {'newDelivery': '8397.000', 'grade': u'Unleaded', 'timestamp': datetime.datetime(2019, 6, 23, 0, 0), 'tanksystemid': 5977, 'oldDelivery': 8397.0, 'sitecode': u'1156'})

When I try to retrieve; dic_a['sitecode'] dic_a['timestamp'] I get;

'int' object has no attribute '__getitem__'

error. What Im doing wrong here?

messageDict looks liek;

{14090233: {'newDelivery': '5009.000', 'grade': u'E10', 'timestamp': datetime.datetime(2019, 6, 21, 0, 0), 'tanksystemid': 5776, 'oldDelivery': 5009.0, 'sitecode': u'4169'}, 14129146: {'newDelivery': '17091.000', 'grade': u'Unleaded', 'timestamp': datetime.datetime(2019, 6, 24, 0, 0), 'tanksystemid': 8720, 'oldDelivery': 17091.0, 'sitecode': u'2328'}, 14118907: {'newDelivery': '13797.000', 'grade': u'Unleaded', 'timestamp': datetime.datetime(2019, 6, 23, 0, 0), 'tanksystemid': 5973, 'oldDelivery': 13797.0, 'sitecode': u'1151'}, 14145533: {'newDelivery': '8281.000', 'grade': u'PULP', 'timestamp': datetime.datetime(2019, 6, 24, 0, 0), 'tanksystemid': 5360, 'oldDelivery': 8281.0, 'sitecode': u'2212'}, 14129150: {'newDelivery': '7099.000', 'grade': u'Diesel', 'timestamp': datetime.datetime(2019, 6, 24, 0, 0), 'tanksystemid': 8724, 'oldDelivery': 7099.0, 'sitecode': u'2328'}, 14129565: {'newDelivery': '16619.100', 'grade': u'Unleaded', 'timestamp': datetime.datetime(2019, 6, 24, 0, 0), 'tanksystemid': 10012, 'oldDelivery': 16619.1, 'sitecode': u'4217'}}

Answer 1

It looks like you only want to iterate the values of the dictionary. If so, you can accomplish this by iterating through messageDict.values() . This also removes the need for the inner for loop:

for dic_a in messageDict.values():
    print dic_a['sitecode']
    print dic_a['sitecode'], dic_a['timestamp'], dic_a['grade'],
          dic_a['newDelivery'], dic_a['oldDelivery']

Answer 2

Other people have already pointed out the problem, I'll just try to explain it a little more as to why it is happening the way it is happening.

Your messageDict is a dictionary with the ObservationRawDataId as key and another dict as value. When you call messageDict.items() , it returns a tuple (ObservationRawDataId, {'timestamp': TimeStamp... , so the first value in the tuple is ObservationRawDataId and not the dic_a as you are expecting it. If you want to iterate over the values, you can do it as @Tomothy32 suggested:

for dic_a in messageDict.values():
    print dic_a['sitecode']
    print dic_a['sitecode'], dic_a['timestamp'], dic_a['grade'],
          dic_a['newDelivery'], dic_a['oldDelivery']

Or if you want to use ObservationRawDataId somewhere in the loop too, you can use:

for rawDataId in messageDict.keys():
    dic_a = messageDict[rawDataId]
    print dic_a['sitecode']
    print dic_a['sitecode'], dic_a['timestamp'], dic_a['grade'],
          dic_a['newDelivery'], dic_a['oldDelivery']

Answer 3

When you iterate through the list returned by messageDict.items() , you get tuples of key-value pairs (in your case int-dict pairs). It seems like you are expecting only the values to be iterated through.

As you mentioned when you print the tuple, you get

(14118912, {'newDelivery': '8397.000', 'grade': u'Unleaded', 'timestamp': datetime.datetime(2019, 6, 23, 0, 0), 'tanksystemid': 5977, 'oldDelivery': 8397.0, 'sitecode': u'1156'})

Note the first object in the tuple. So through the first iteration of the inner loop, the variable dic_a stores 14118912 and calling dic_a['sitecode'] is what causes an error as an int object of course does not support this (This must be the __getitem__ attribute error thrown).

What I think you wanted to do is call messageDict.values() which only returns a list of the values (in your case a list of dictionary objects) in the dictionary.