Python PyMongo获取筛选器必须是dict的实例，bson.son.son错误

下面是我试图运行的python代码。但是，我得到一个错误，它说

TypeError: filter must be an instance of dict, bson.son.SON, or any other type that inherits from collections.Mapping



query = db.collections.table.find({ "$and": [ { "time": { "$gte" : 5000 } }, { "time" : { "$lte": 10000 } }, { "blt_id":20} ] })

projection = db.collections.table.find({ "alt_id": 1, "time": 1, "__id": 0})

for doc in db.collections.table.find(query, projection):
    print(doc)

---

如何解决此问题？

query

和

projection

应该是

dict

s；通过一些优化，您的代码应该是：

query = {"time": {"$gte": 5000, "$lte": 10000}, "blt_id": 20}
projection = {"alt_id": 1, "time": 1, "_id": 0}

for doc in db.collections.table.find(query, projection):
    print(doc)