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While retrieving the contents of a collection, you can sort and arrange them in ascending or descending orders using the sort() method.
To this method, you can pass the field(s) and the sorting order which is 1 or -1. Where, 1 is for ascending order and -1 is descending order.
Syntax
Following is the syntax of the sort() method.
>db.COLLECTION_NAME.find().sort({KEY:1})
Example
Assume we have created a collection and inserted 5 documents into it as shown below −
> use testDB switched to db testDB > db.createCollection("myColl") { "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 all the documents of the collection which are sorted in ascending order based on age.
> db.sample.find().sort({age:1}) { "_id" : "1005", "name" : "Sarmista", "age" : 23, "city" : "Delhi" } { "_id" : "1004", "name" : "Romeo", "age" : 25, "city" : "Pune" } { "_id" : "1006", "name" : "Rasajna", "age" : 26, "city" : "Chennai" } { "_id" : "1002", "name" : "Rahim", "age" : 27, "city" : "Bangalore" } { "_id" : "1003", "name" : "Robert", "age" : 28, "city" : "Mumbai" } { "_id" : "1001", "name" : "Ram", "age" : "26", "city" : "Hyderabad" }
Sorting the documents using python
To sort the results of a query in ascending or, descending order pymongo provides the sort() method. To this method, pass a number value representing the number of documents you need in the result.
By default, this method sorts the documents in ascending order based on the specified field. If you need to sort in descending order pass -1 along with the field name −
coll.find().sort("age",-1)
Example
Following example retrieves all the documents of a collection arranged according to the age values in ascending order −
from pymongo import MongoClient #Creating a pymongo client client = MongoClient(''localhost'', 27017) #Getting the database instance db = client[''b_mydb''] #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("List of documents (sorted in ascending order based on age): ") for doc1 in coll.find().sort("age"): print(doc1)
Output
Data inserted ...... List of documents (sorted in ascending order based on age): {''_id'': ''1005'', ''name'': ''Sarmista'', ''age'': 23, ''city'': ''Delhi''} {''_id'': ''1004'', ''name'': ''Romeo'', ''age'': 25, ''city'': ''Pune''} {''_id'': ''1006'', ''name'': ''Rasajna'', ''age'': 26, ''city'': ''Chennai''} {''_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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