没有找到mongoDB的去重功能，自己写一个，利用分组计数功能，找到count>1的记录，逐一删除重复记录

import pymongo

def mongo_dup_remove(db,col,*args):
    #对指定集合去重
    #未考虑数据排序
    #支持多个参数
    myclient = pymongo.MongoClient("mongodb://localhost:27017/")
    mydb = myclient[db]
    mycol = mydb[col]
    project={'_id':0}
    project.update({x:1 for x in args})
    id_={x:f'${x}' for x in args}
    group={'_id':id_}
    group.update({"count":{"$sum":1}})
    pipeline=[
            {'$project':project},
            {'$group':group},
            {"$match": {
                        "count": {"$gt": 1}
                        }
            }
            ]
    for col in mycol.aggregate(pipeline):
        query=col['_id']
        count=col['count']
        while mycol.count_documents(query) > 1:
            mycol.delete_one(query)
        print(f'已删除：{query}，重复数：{count}')
    return