Python MongoDB – Limit
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While retrieving the contents of a collection you can limit the number of documents in the result using the limit() method. This method accepts a number value representing the number of documents you want in the result.
Syntax
Following is the syntax of the limit() method −
>db.COLLECTION_NAME.find().limit(NUMBER)
Example
Assume we have created a collection and inserted 5 documents into it as shown below −
> use testDB
switched to db testDB
> db.createCollection(“sample”)
{ “ok” : 1 }
> data = [
… {“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”},
… {“_id”: “1002”, “name”: “Rahim”, “age”: 27, “city”: “Bangalore”},
… {“_id”: “1003”, “name”: “Robert”, “age”: 28, “city”: “Mumbai”},
… {“_id”: “1004”, “name”: “Romeo”, “age”: 25, “city”: “Pune”},
… {“_id”: “1005”, “name”: “Sarmista”, “age”: 23, “city”: “Delhi”},
… {“_id”: “1006”, “name”: “Rasajna”, “age”: 26, “city”: “Chennai”}
]
> db.sample.insert(data)
BulkWriteResult({
“writeErrors” : [ ],
“writeConcernErrors” : [ ],
“nInserted” : 6,
“nUpserted” : 0,
“nMatched” : 0,
“nModified” : 0,
“nRemoved” : 0,
“upserted” : [ ]
})
Following line retrieves the first 3 documents of the collection.
> db.sample.find().limit(3)
{ “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad” }
{ “_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore” }
{ “_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” }
Limiting the Documents Using Python
To restrict the results of a query to a particular number of documents pymongo provides the limit() method. To this method pass a number value representing the number of documents you need in the result.
Example
Following example retrieves first three documents in a collection.
from pymongo import MongoClient
#Creating a pymongo client
client = MongoClient(”localhost”, 27017)
#Getting the database instance
db = client[”l”]
#Creating a collection
coll = db[”myColl”]
#Inserting document into a collection
data = [
{“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”},
{“_id”: “1002”, “name”: “Rahim”, “age”: “27”, “city”: “Bangalore”},
{“_id”: “1003”, “name”: “Robert”, “age”: “28”, “city”: “Mumbai”},
{“_id”: “1004”, “name”: “Romeo”, “age”: 25, “city”: “Pune”},
{“_id”: “1005”, “name”: “Sarmista”, “age”: 23, “city”: “Delhi”},
{“_id”: “1006”, “name”: “Rasajna”, “age”: 26, “city”: “Chennai”}
]
res = coll.insert_many(data)
print(“Data inserted ……”)
#Retrieving first 3 documents using the find() and limit() methods
print(“First 3 documents in the collection: “)
for doc1 in coll.find().limit(3):
print(doc1)
Output
Data inserted ……
First 3 documents in the collection:
{”_id”: ”1001”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”}
{”_id”: ”1002”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Bangalore”}
{”_id”: ”1003”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”}
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