python - 数据库字段排序问题

Question

1、数据库
{'cishu': 372, 'title': '镇中心小学厕所问题'}
{'cishu': 388, 'title': '私搭乱建'}
{'cishu': 222, 'title': '新生儿落户收费么？'}
{'cishu': 341, 'title': '44路车不按时间发车越来越严重'}

2、我想以cishu为参考做个排序

for i in info.find({},{'title':1,'_id':0}).sort({"cishu":-1}):
    print(i)

我写了这个进行排序，总是报错，刚初学，不知道怎么做这个排序。。。
报错内容

TypeError: if no direction is specified, key_or_list must be an instance of list

3、弄不明白之后，然后我尝用管道进行排序，倒是出来了结果，只有次数，不会把title弄出来。。。

def cishu():
    pipeline = [
        {'$group': {'_id':'$cishu'}},
        {'$sort':{'_id':-1}},
        {'$limit':100}
    ]
    for i in item_info.aggregate(pipeline):
        data = {
            'name': i['_id'],

        }
        print(i)

出来的结果是
{'_id': 388}
{'_id': 372}
{'_id': 341}
{'_id': 222}

我想要的结果是
{'cishu': 388, 'title': '私搭乱建'}
{'cishu': 372, 'title': '镇中心小学厕所问题'}
{'cishu': 341, 'title': '44路车不按时间发车越来越严重'}
{'cishu': 222, 'title': '新生儿落户收费么？'}

我怎么让他全面的出来结果。。。小白苦恼，请大侠帮忙看看

Answer 1

Writing like this in sort [("cishu",pymongo.DESCENDING)], if multi-value sorting is [("key1",pymongo.DESCENDING),("key2":pymongo.DESCENDING)]. See the code for details

from pymongo import MongoClient
import pymongo
client = MongoClient()
#创建连接
conn = MongoClient('127.0.0.1', 27017)
#连接数据库
db = conn.qwer
datas = db.test.find({}, {"cishu":1,"title":1,"_id":0}).sort([("cishu",pymongo.DESCENDING)])
for data in datas:
    print(data)

Answer 2

Code:

info = [
    {'cishu': 372, 'title': '镇中心小学厕所问题'},
    {'cishu': 388, 'title': '私搭乱建'},
    {'cishu': 222, 'title': '新生儿落户收费么？'},
    {'cishu': 341, 'title': '44路车不按时间发车越来越严重'}
]

for item in sorted(info, key=lambda dic: dic['cishu'], reverse=True):
    print(item)

Result:

{'cishu': 388, 'title': '私搭乱建'}
{'cishu': 372, 'title': '镇中心小学厕所问题'}
{'cishu': 341, 'title': '44路车不按时间发车越来越严重'}
{'cishu': 222, 'title': '新生儿落户收费么？'}

---

Questions I answered: Python-QA

Answer 3

Why not sort when querying the database?

select * from xxx order by cishu desc