How to add key,value pair to dictionary?.Below i have mentioned following format?

{'1_somemessage': [[3L, 1L, u'AAA', 1689544L, datetime.datetime(2010, 9, 21, 22, 30), u'gffggf'], [3L, 1L, u'BBB', 1689544L, datetime.datetime(2010, 9, 21, 20, 30), u'ffgffgfg'], [3L, 1L, u'CCC', 1689544L, datetime.datetime(2010, 9, 21, 22, 30), u'hjhjhjhj'], [3L, 1L, u'DDD', 1689544L, datetime.datetime(2010, 9, 21, 21, 45), u'jhhjjh']], '2_somemessage': [[4L, 1L, u'AAA', 1689544L, datetime.datetime(2010, 9, 21, 22, 30), u'gffggf'], [4L, 1L, u'BBB', 1689544L, datetime.datetime(2010, 9, 21, 20, 30), u'ffgffgfg'], [4L, 1L, u'CCC', 1689544L, datetime.datetime(2010, 9, 21, 22, 30), u'hjhjhjhj'], [4L, 1L, u'DDD', 1689544L, datetime.datetime(2010, 9, 21, 21, 45), u'jhhjjh']]}
0

7 Answers

Add a key, value pair to dictionary 

aDict = {} aDict[key] = value

What do you mean by dynamic addition.

3

For quick reference, all the following methods will add a new key 'a' if it does not exist already or it will update the existing key value pair with the new value offered:

data['a']=1 data.update({'a':1}) data.update(dict(a=1)) data.update(a=1)

You can also mixing them up, for example, if key 'c' is in data but 'd' is not, the following method will updates 'c' and adds 'd'

data.update({'c':3,'d':4})
6

I am not sure what you mean by "dynamic". If you mean adding items to a dictionary at runtime, it is as easy as dictionary[key] = value.

If you wish to create a dictionary with key,value to start with (at compile time) then use (surprise!) 

dictionary[key] = value

I got here looking for a way to add a key/value pair(s) as a group - in my case it was the output of a function call, so adding the pair using dictionary[key] = value would require me to know the name of the key(s).

In this case, you can use the update method: dictionary.update(function_that_returns_a_dict(*args, **kwargs)))

Beware, if dictionary already contains one of the keys, the original value will be overwritten.

May be some time this also will be helpful

import collections #Write you select statement here and other things to fetch the data. if rows: JArray = [] for row in rows: JArray2 = collections.OrderedDict() JArray2["id"]= str(row['id']) JArray2["Name"]= row['catagoryname'] JArray.append(JArray2) return json.dumps(JArray)

Example Output:

[ { "id": 14 "Name": "someName1" }, { "id": 15 "Name": "someName2" } ]

If you want to add a new record in the form

newRecord = [4L, 1L, u'DDD', 1689544L, datetime.datetime(2010, 9, 21, 21, 45), u'jhhjjh']

to messageName where messageName in the form X_somemessage can, but does not have to be in your dictionary, then do it this way:

myDict.setdefault(messageName, []).append(newRecord)

This way it will be appended to an existing messageName or a new list will be created for a new messageName.

1

To insert/append to a dictionary

{"0": {"travelkey":"value", "travelkey2":"value"},"1":{"travelkey":"value","travelkey2":"value"}} travel_dict={} #initialize dicitionary travel_key=0 #initialize counter if travel_key not in travel_dict: #for avoiding keyerror 0 travel_dict[travel_key] = {} travel_temp={val['key']:'no flexible'} travel_dict[travel_key].update(travel_temp) # Updates if val['key'] exists, else adds val['key'] travel_key=travel_key+1