Question

这是一些示例文档（我只显示用过的文件，文档中还有其他字段）：

{"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}}

根据https://docs.mongodb.com/manual/reference/operator/aggregation/bucket/index.html，我想做的是计算分数分布，我使用存储桶操作。

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))

但是，我遇到了错误：

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

我找不到类型错误的原因，有人可以提出建议吗？

Answer 1

对不起，我犯了一个超级编辑错误。管道应为数组，而不是字典。

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}
            }
        }}
    ]

MongoDB存储桶操作具有不可散列的类型：mongoEngine

1 个答案: