Python MongoDB – Limit


Python MongoDB – Limit



”;


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''}

Advertisements

”;

Leave a Reply

Your email address will not be published. Required fields are marked *