PyMongo TypeError

Question

I have a python script in which I'm using pymongo to aggregate collections and perform certain operations on them if the sum of a particular aggregate is greater than a number (in this case, 30).

  agg = collection.aggregate([{"$match":{"valid":1}}, {"$group": {"_id": {"createdby" : "$createdby" ,"addedtime" : "$addedtime", "empname" : "$empname"}, "count":{"$sum":1}}}])

  cnt = 0
  for eachAgg in agg:
    print "eachAgg = ",eachAgg
    if eachAgg['count'] >= 30:

When I run this script, I'm getting

  eachAgg = ok
  Traceback (most recent call last): 
  File "test.py", line 33, in <module>
  if eachAgg['count'] >= 30: 
  TypeError: string indices must be integers

I don't understand how $sum aggregate is not an integer.

Answer 1

agg: returns a more detailed dict with the result of aggregation i.e.:

    { 
      u'ok': 1.0, 
      u'waitedMS': 0L, 
      u'result': [<your actual aggregation result>]
    }

That's why you get TypeError: string indices must be integers, cause you iterate over keys in the dict (for eachAgg in agg) , where a key is string and string indices must be integers.

The real data result it is in agg['result'], try:

for eachAgg in agg['result']:
    if eachAgg['count'] >= 30:
    ....