Python-字典中的Pymongo列表

Question

I'm new to python.

what I have:

I am using mongoDb and python. Using distinct dates, I want to retrieve all comments from that date.

example datebase:

id|created_time|comment |.....
0 |2014-01-01  | hi!    |......
1 |2014-02-01  | hello! |......
2 |2014-01-01  | bye    |......`

what I tried:

text = db.comments.find(timeout=False)
time = db.comments.distinct('created_time')

#some code
#get all distinct date and put into list
timeArray = []
for allTime in time:
    timeArray.append(allTime)

comDict = {}
for allCom in text:
    global comDict
    if(allCom['created_time'] == timeArray[1]):

        #note i'm used timeArray[1] to test the code.

        comDict.update({allCom['created_time']:allCom['comments']})

print comDict

dict cannot have duplicated keys, therefore the .update keep changing the value instead of appending it but i don't know of other way.

what I need:

{2014-01-01:['hi','bye'], 2014-02-01:['Hello!']}

I hope to get the above result but I am not sure how to do that. Can someone enlighten me as to what I should do, or what I did wrong?

Thanks in advance!

Answer 1

Don't solve it on the python level, let mongodb group the records using aggregate() :

pipe = [
    {'$match': {'$timeout': False}},
    {'$group': {'_id': '$created_time', 
                'comments': {'$push': '$comments'}}},
]
db.comments.aggregate(pipeline=pipe)

Answer 2

If you really want to use python:

dict0={}
if not 'date' in dict0.keys(): dict0['date']=[value]
else: dict0['date'].append(value)