how to write mongodb query in python for db.collection.group()

Question

I am working on a MongoDB query

db.BH.group({
"key": {
    "AccountId": true,
},
"initial": {
    "count": 0
},
"reduce": function(obj, prev) {
    if (true != null) if (true instanceof Array) prev.count += true.length;
    else prev.count++;
},
"cond":     
    {"$or":[{"Url":{"$regex":"(google)"}},{"Url":{"$regex":"(facebook)"}}]} 
});

The query is working fine in MongoDB Shell(Robomongo).

I have written the same query for python.

db.BH.group({
"key": {
    "AccountId": True,
},
"initial": {
    "count": 0
},
"reduce": "function(obj, prev) {"
    "if (true != null) if (true instanceof Array) prev.count += true.length;"
    "else prev.count++;"
"}",
"cond": {"$or":[{"Url":{"$regex":"(google)"}},{"Url":{"$regex":"(facebook)"}}]} 
})

But error is coming for the query.

TypeError: group() takes at least 5 arguments (2 given)

I tried to solve the error from the method given in the below website(URL)

http://blog.pythonisito.com/2012/05/aggregation-in-mongodb-part-1.html

But the same error persists.

score 1 · Answer 1 · answered Mar 16 '15 at 14:36

1

The syntax of group is different in PyMongo. Each of the keys key, initial, etc. in the argument object in Javascript is a keyword argument in Python:

db.BH.group(key = , initial = , reduce = , cond = )

answered Mar 16 '15 at 14:36

wdberkeley

11,531
1
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23

I corrected the syntax but still getting the error **TypeError: group() takes at least 5 arguments (4 given)** @wdberkeley – abhyuday Mar 16 '15 at 19:20

score 0 · Answer 2 · answered Apr 09 '15 at 09:56

group(key, condition, initial, reduce, finalize=None, **kwargs)

You are missing the last parameter "finalize" for the group operation. Using finalize=None should solve the problem.

db.BH.group({
    {
        "AccountId": True,
    },
    {"$or":[{"Url":{"$regex":"(google)"}},{"Url":{"$regex":"(facebook)"}}]}, 
    {
        "count": 0
    },
    "function(obj, prev) {"
        "if (true != null) if (true instanceof Array) prev.count += true.length;"
        "else prev.count++;"
    "}",
    None
})

how to write mongodb query in python for db.collection.group()

2 Answers2