Python MongoDB Begræns

begræns resultater

For at begrænse resultaterne i MongoDB bruger vi limit() metoden.

limit() Metoden accepterer en parameter, der definerer det numeriske antal dokumenter, der returneres.

Antag, at du har en "kunder"-samling:

Kunder

{'_id': 1, 'name': 'John', 'address': 'Highway37'}
{'_id': 2, 'name': 'Peter', 'address': 'Lowstreet 27'}
{'_id': 3, 'name': 'Amy', 'address': 'Apple st 652'}
{'_id': 4, 'name': 'Hannah', 'address': 'Mountain 21'}
{'_id': 5, 'name': 'Michael', 'address': 'Valley 345'}
{'_id': 6, 'name': 'Sandy', 'address': 'Ocean blvd 2'}
{'_id': 7, 'name': 'Betty', 'address': 'Green Grass 1'}
{'_id': 8, 'name': 'Richard', 'address': 'Sky st 331'}
{'_id': 9, 'name': 'Susan', 'address': 'One way 98'}
{"_id": 10, "name": "Vicky", "address": "Yellow Garden 2"}
{"_id": 11, "name": "Ben", "address": "Park Lane 38"}
{"_id": 12, "name": "William", "address": "Central st 954"}
{"_id": 13, "name": "Chuck", "address": "Main Road 989"}
{"_id": 14, "name": "Viola", "address": "Sideway 1633"}

Eksempel

Begræns resultaterne til kun at returnere 5 dokumenter:

import pymongo
myclient = pymongo.MongoClient("mongodb://localhost:27017/")
mydb = myclient["mydatabase"]
mycol = mydb["customers"]
myresult = mycol.find().limit(5)
# Print resultaterne:
for x in myresult:
  print(x)

Kør Eksempel