CODEWITHSUNDEEP
pythonmongodbpymongomongoengine
McCree Feng
McCree Feng

Reputation: 219

MongoDB bucket operation with unhashable type: 'dict' in mongoEngine

Here is some sample document(I only show used filed, there are other fields in document):

{"id":1111,"info":{"score":90,"class":"algorithm","room":101}}
{"id":1112,"info":{"score":60,"class":"java","room":401}}
{"id":1113,"info":{"score":100,"class":"python","room":301}}

What I want do is to compute the score distribution, I use the bucket operation, according to https://docs.mongodb.com/manual/reference/operator/aggregation/bucket/index.html。

pipeline = {
        {"$match": {"_id": ObjectId(_id)}},
        {"$bucket": {
            "groupBy": "$info.score",
            "boundaries": [0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100],
            "output": {
                "count": {"$sum": 1}
            }
        }}
    }
score_distribution = list(Students.objects.aggregate(*pipeline))

However, I met the error:

"count": {"$sum": 1}
TypeError: unhashable type: 'dict'

I can't find the reason why there is type error, can anyone give some suggestion?

Upvotes: 0

Views: 660

Answers (1)

McCree Feng
McCree Feng

Reputation: 219

Sorry guys, I made a super edit mistake. The pipeline should be array not a dict.

pipeline = [
        {"$match": {"_id": ObjectId(_id)}},
        {"$bucket": {
            "groupBy": "$info.score",
            "boundaries": [0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100],
            "output": {
                "count": {"$sum": 1}
            }
        }}
    ]

Upvotes: 1

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