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Let us first create a collection with documents −> dbmongoDBCollectionSizeDemoinsertOne({"Name":"John", "Age":23}); { "acknowledged" : true, "insertedId" : ObjectId("5cf23e3db64a577be5a2bc16") } > dbmongoDBCollectionSizeDemoinsertOne({"Name":"Chris", "Age":24}); { "acknowledged" : true, "insertedId" : ObjectId("5cf23e45b64a577be5a2bc17") } > dbmongoDBCollectionSizeDemoinsertOne({"Name":"Robert", "Age":26}); { "acknowledged" : true, "insertedId" : ObjectId("5cf23e4db64a577be5a2bc18") }Following is the query to display all documents from a collection with the help of find() method −> dbmongoDBCollectionSizeDemofind();This will produce the following document −{ "_id" : ObjectId("5cf23e3db64a577be5a2bc16"), "Name" : "John", "Age" : 23 } { "_id" : ObjectId("5cf23e45b64a577be5a2bc17"), "Name" : "Chris", "Age" : 24 } { "_id" : ObjectId("5cf23e4db64a577be5a2bc18"), "Name" : "Robert", "Age" ... Read More
Math.hypot()Math.Hypot() method is used to find the square root of the sum of the squares of the elements that are passed to it as arguments. This method is actually used to find the hypotenuse of a right-angle triangle whose sides are passed as arguments into it. syntaxMath.hypot(arg1, arg2, ....);ExampleIn the following example, sides of a right-angle triangle are passed to find the hypotenuse. If any value is can't be converted to a number then NaN will be displayed as output. Live Demo document.write(Math.hypot(7, 24)); document.write(""); document.write(Math.hypot(7, "hi")); Output25 NaNThis ... Read More
The HTML DOM Input URL form property returns the reference of enclosing form for input URL.SyntaxFollowing is the syntax −Returning reference to the form objectinputURLObject.formExampleLet us see an example of Input URL form property − Live Demo Input URL form form { width:70%; margin: 0 auto; text-align: center; } * { padding: 2px; margin:5px; } input[type="button"] { border-radius: 10px; } URL-form URL : ... Read More
Sometimes we see that there are two types of main function definition. The int main() and int main(void). So is there any difference?In C++, there is no difference. In C also both are correct. But the second one is technically better. It specifies that the function is not taking any argument. In C if some function is not specified with the arguments, then it can be called using no argument, or any number of arguments. Please check these two codes. (Remember these are in C not C++)Example#include void my_function() { //some task } main(void) { my_function(10, "Hello", "World"); ... Read More
To change text font, you can use the setFont() method of JLabel −label.setFont(new Font("Verdana", Font.PLAIN, 12));The following is an example to change text font for JLabel with HTML −Exampleimport java.awt.Font; import javax.swing.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Label Example"); JLabel label; label = new JLabel("" + "ABC"); label.setBounds(50, 50, 100, 30); label.setFont(new Font("Verdana", Font.PLAIN, 12)); frame.add(label); frame.setSize(500,300); frame.setLayout(null); frame.setVisible(true); } }Output
itermonthdates() method will return all days for the month and all days before the start of the month or after an end of the month that are required to get a complete week.Exampleimport calendar #assigning variable to the calendar variable = calendar.Calendar() for day in variable.itermonthdates(2019, 5): print(day)Output2019-04-29 2019-04-30 2019-05-01 2019-05-02 2019-05-03 2019-05-04 2019-05-05 2019-05-06 2019-05-07 2019-05-08 2019-05-09 2019-05-10 2019-05-11 2019-05-12 2019-05-13 2019-05-14 2019-05-15 2019-05-16 2019-05-17 2019-05-18 2019-05-19 2019-05-20 2019-05-21 2019-05-22 2019-05-23 2019-05-24 2019-05-25 2019-05-26 2019-05-27 2019-05-28 2019-05-29 2019-05-30 2019-05-31 2019-06-01 2019-06-02Important to rememberlook into the output that calendar shows starts the previous month's date and ends with the after ... Read More
Let’s say we want the first child node of a node, then use the getFirstChild() method −node2.getFirstChild()Display the node’s first child on Console −System.out.println("The first child of node 2 = "+node2.getFirstChild());The following is an example to get this node’s first child in a JTree −package my; import javax.swing.JFrame; import javax.swing.JTree; import javax.swing.tree.DefaultMutableTreeNode; public class SwingDemo { public static void main(String[] args) throws Exception { JFrame frame = new JFrame("Demo"); DefaultMutableTreeNode node = new DefaultMutableTreeNode("Products"); DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("Clothing (Product1 - P66778)"); DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Accessories ... Read More
Set the following to FALSE to enable the display of hidden files −JFileChooser file = new JFileChooser(); file.setFileHidingEnabled(false);The following is an example to enable the display of hidden files in a JFileChooser −Examplepackage my; import javax.swing.JFileChooser; public class SwingDemo { public static void main(String[] args) { JFileChooser file = new JFileChooser(); file.setMultiSelectionEnabled(false); file.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES); file.setFileHidingEnabled(false); int res = file.showOpenDialog(null); if (res == JFileChooser.APPROVE_OPTION) { java.io.File f = file.getSelectedFile(); System.err.println(f.getPath()); } ... Read More
Let us first create a collection with documents −> db.queryForPartialObjectDemo.insertOne({_id:new ObjectId(), "StudentDetails": [{"StudentId":1, "StudentName":"Chris"}]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdfcf55bf3115999ed51206") } > db.queryForPartialObjectDemo.insertOne({_id:new ObjectId(), "StudentDetails": [{"StudentId":2, "StudentName":"David"}]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdfcf55bf3115999ed51207") }Following is the query to display all documents from a collection with the help of find() method −> db.queryForPartialObjectDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cdfcf55bf3115999ed51206"), "StudentDetails" : [ { "StudentId" : 1, "StudentName" : "Chris" } ] } { "_id" ... Read More
SQL databases provide a datatype named Blob (Binary Large Object) in this, you can store large binary data like images.To store binary (stream) values into a table JDBC provides a method called setBinaryStream() in the PreparedStatement interface.It accepts an integer representing the index of the bind variable representing the column that holds values of type BLOB, an InputStream object holding the binary data and, inserts the given data in to the specified column.You can insert binary stream data into a table using this method as shown below −FileInputStream fin = new FileInputStream("javafx_logo.jpg"); pstmt.setBinaryStream(3, fin);ExampleLet us create a table with name ... Read More