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First, set a two-dimensional array.int[, ] arr = new int[10, 10];Now, get the elements from the user −for (i = 0; i < m; i++) { for (j = 0; j < n; j++) { arr[i, j] = Convert.ToInt16(Console.ReadLine()); } }Let us see the complete example to display the matrix.Example Live Demousing System; using System.Linq; class Demo { static void Main() { int m, n, i, j; // rows and columns of the matrix+ m = 2; n = ... Read More
For this, use $pull along with update. Let us create a collection with documents −> db.demo198.insertOne({"List":{"Values":[10, 20, 30, 30, 70, 80, 90]}}); { "acknowledged" : true, "insertedId" : ObjectId("5e3c224503d395bdc21346df") } > db.demo198.insertOne({"List":{"Values":[56, 978, 56, 34, 23, 34]}}); { "acknowledged" : true, "insertedId" : ObjectId("5e3c225403d395bdc21346e0") } > db.demo198.insertOne({"List":{"Values":[21, 12, 14, 15, 34, 56]}}); { "acknowledged" : true, "insertedId" : ObjectId("5e3c226603d395bdc21346e1") }Display all documents from a collection with the help of find() method −> db.demo198.find();This will produce the following output −{ "_id" : ObjectId("5e3c224503d395bdc21346df"), "List" : { "Values" : [ 10, 20, 30, 30, 70, 80, ... Read More
No, using LIMIT() decreases the bandwidth consumption and it does not increase query speed. Let us see an example and create a collection with documents −> db.demo197.insertOne({"Name":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3afde803d395bdc21346d8") } > db.demo197.insertOne({"Name":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3afdef03d395bdc21346d9") } > db.demo197.insertOne({"Name":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3afdf203d395bdc21346da") } > db.demo197.insertOne({"Name":"Sam"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3afdf603d395bdc21346db") } > db.demo197.insertOne({"Name":"Mike"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3afdf903d395bdc21346dc") } > db.demo197.insertOne({"Name":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3afe1603d395bdc21346dd") } > db.demo197.insertOne({"Name":"John"}); { ... Read More
Let us create a collection with documents −> db.demo196.insertOne( ... { ... ... "Id" : "101", ... "details" : [ ... { ... "FirstName" : "Chris", ... "LastName" : "Brown", ... "Score" : 45 ... }, ... { ... "FirstName" : "David", ... "LastName" : "Miller", ... "Score" : 87 ... ... Read More
To return a list of specific values, use map(). Let us create a collection with documents −> db.demo195.insertOne({"Subject":"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3af3f203d395bdc21346d4") } > db.demo195.insertOne({"Subject":"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3af3f703d395bdc21346d5") } > db.demo195.insertOne({"Subject":"Java"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3af3fa03d395bdc21346d6") }Display all documents from a collection with the help of find() method −> db.demo195.find();This will produce the following output −{ "_id" : ObjectId("5e3af3f203d395bdc21346d4"), "Subject" : "MySQL" } { "_id" : ObjectId("5e3af3f703d395bdc21346d5"), "Subject" : "MongoDB" } { "_id" : ObjectId("5e3af3fa03d395bdc21346d6"), "Subject" : "Java" }Following is the query to return a ... Read More
Let us first create a collection with documents −> db.demo194.insertOne( ... { ... "_id": 101, ... "details": { ... "otherDetails": { ... "List1": ["MongoDB", "MySQL"], ... "List2": ["Java"], ... "List3": ["MongoDB", "C"] ... } ... } ... } ...); { "acknowledged" : true, "insertedId" : 101 } > db.demo194.insertOne( {"_id": 102, "details": { "otherDetails": { "List1": ["Java", "C"], "List2": ["C++"], "List3": ["Python", "Spring"] } } } ... Read More
The Join () method in strings concatenates all the elements of a string array, using the specified separator between each element.In the below example we have a multi-line string and we have set the separator as “” −String.Join("", starray);ExampleThe following is the complete example − Live Demousing System; namespace StringApplication { class StringProg { static void Main(string[] args) { string[] starray = new string[]{"Down the way nights are dark", "And the sun shines daily on the mountaintop", "I took ... Read More
To improve the execution time of a query, use index along with unique:true. Let us create a collection with documents −> db.demo193.createIndex({"LastName":1}, {unique:true}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo193.insertOne({"FirstName":"John", "LastName":"Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ade1803d395bdc21346d1") } > db.demo193.insertOne({"FirstName":"John", "LastName":"Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ade1f03d395bdc21346d2") } > db.demo193.insertOne({"FirstName":"David", "LastName":"Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ade2803d395bdc21346d3") }Display all documents from a collection with the help of find() method −> db.demo193.find();This will produce the following output −{ "_id" ... Read More
To group several fields, use $group in MongoDB. Let us create a collection with documents −> db.demo192.insertOne({"Name":"Chris", "Age":22}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adb9f03d395bdc21346cd") } > db.demo192.insertOne({"Name":"David", "Age":21}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adba103d395bdc21346ce") } > db.demo192.insertOne({"Name":"Chris", "Age":22}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adba503d395bdc21346cf") } > db.demo192.insertOne({"Name":"Mike", "Age":24}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adbbf03d395bdc21346d0") }Display all documents from a collection with the help of find() method −> db.demo192.find();This will produce the following output −{ "_id" : ObjectId("5e3adb9f03d395bdc21346cd"), "Name" : "Chris", "Age" : 22 } { "_id" : ObjectId("5e3adba103d395bdc21346ce"), ... Read More
To get values of cursor in MongoDB, use hasNext(). Let us create a collection with documents −> db.demo191.insertOne({"EmployeeId":1, "EmployeeName":"Chris Brown"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad95303d395bdc21346c5") } > db.demo191.insertOne({"EmployeeId":2, "EmployeeName":"David Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad95f03d395bdc21346c6") } > db.demo191.insertOne({"EmployeeId":1, "EmployeeName":"John Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad96803d395bdc21346c7") } > db.demo191.insertOne({"EmployeeId":1, "EmployeeName":"John Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad97003d395bdc21346c8") }Display all documents from a collection with the help of find() method −> db.demo191.find();This will produce the following output −{ "_id" : ObjectId("5e3ad95303d395bdc21346c5"), "EmployeeId" : 1, "EmployeeName" : "Chris ... Read More