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Articles by George John
Page 52 of 79
How to order by a custom rule like order like 4,2,1,3 in MySQL?
To order with a custom rule, use the ORDER BY FIELD(). Let us first create a table −mysql> create table DemoTable ( Number int ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(4); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(2); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(3); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> ...
Read MoreMathematical Functions in Python?
From doing simple to complex mathematical operations(like trigonometric, logarithmic operations etc) in python we may need to use the math() module.The python math module is used to access mathematical functions. All methods of math() function are used for integer or real type objects but not for complex numbers.To use this function, we need to import it in our codeimport mathConstantsWe use these constants for calculation in python -ConstantsDescriptionsPiReturn the value of pi: 3.141592EReturn the value of natural base e. e is 0.718282tauReturns the value of tau. tau = 6.283185infReturns the infinitenanNot a number typeNumbers and Numeric RepresentationPython provides different functions ...
Read MoreHow to set vertical gap between elements in a GridLayout with Java?
Use the setVgap() method to set the vertical gap between elements in a GridLayout. Let’s say we have a GridLaypout −GridLayout layout = new GridLayout(3, 3);Set the horizontal gap −layout.setVgap(30);The following is an example −Examplepackage my; import java.awt.Color; import java.awt.Dimension; import java.awt.FlowLayout; import java.awt.Font; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JTextArea; import javax.swing.WindowConstants; public class SwingDemo { public static void main(String[] args) { JFrame frame = new JFrame("Sections"); JPanel panel = new JPanel(); panel.setBackground(Color.blue); GridLayout layout = new GridLayout(3, 3); ...
Read MoreHow can I separate Menu Items in a Menu with Java?
Let’s say we have following MenuBar and menu in it -JMenuBar menuBar = new JMenuBar(); UIManager.put("MenuBar.background", Color.ORANGE); JMenu fileMenu = new JMenu("File"); fileMenu.setMnemonic(KeyEvent.VK_F); menuBar.add(fileMenu);Now, we will create a MenuItem and separate it using the JSeparator():JMenuItem menuItem1 = new JMenuItem("New", KeyEvent.VK_N); fileMenu.add(menuItem1); // separating MenuItems fileMenu.add(new JSeparator());The following is an example to separate Menu Items in a Menu with Java -Examplepackage my; import java.awt.Color; import java.awt.event.KeyEvent; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.JSeparator; import javax.swing.UIManager; public class SwingDemo { public static void main(final String args[]) { JFrame frame = new JFrame("MenuBar Demo"); ...
Read MoreSet whether the row in the table model can be selected or deselected in Java?
We can set or disallow selection of row in the table using setRowSelectionAllowed().Let’s say the following is our table −DefaultTableModel tableModel = new DefaultTableModel(); JTable table = new JTable(tableModel);If you want to allow selection of row, then set the method to TRUE −table.setRowSelectionAllowed(true);If you want to disallow selection of row, then set the method to FALSE −table.setRowSelectionAllowed(false);We have disallowed selection of rows in the below example −Examplepackage my; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.DefaultTableModel; public class SwingDemo { public static void main(String[] argv) throws Exception { DefaultTableModel tableModel = new DefaultTableModel(); ...
Read MoreDisplay all the titles of JTabbedPane tabs on Console in Java
To display all the titles of the JTabbedPane, let us first get the count of tabs −int count = tabbedPane.getTabCount();Now, loop through the number of tabs in the JTabbedPane. Use the getTitleAt() to get the title of each and every tab −for (int i = 0; i < count; i++) { String str = tabbedPane.getTitleAt(i); System.out.println(str); }The following is an example to display all the titles of JTabbedPane tabs on Console −Examplepackage my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Devices"); ...
Read MoreHow to set magins between cells of a JTable in Java?
To set the margins i.e. row and columns margins between cells of a table, use the setIntercellSpacing() method −Dimension dim = new Dimension(50, 2); table.setIntercellSpacing(new Dimension(dim));Above, we have used the Dimension class −The following is an example to set margins between cells of a JTable cell −Examplepackage my; import java.awt.Dimension; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JRootPane; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.DefaultTableModel; public class SwingDemo { public static void main(String[] argv) throws Exception { JFrame frame = new JFrame("Demo"); JPanel panel = new JPanel(); String data[][] = { ...
Read MoreHow to retrieve the value from a table cell with TableModel in Java?
At first, create a table with DefaultTableModel −String data[][] = { {"Australia", "5", "1"}, {"US", "10", "2"}, {"Canada", "9", "3"}, {"India", "7", "4"}, {"Poland", "2", "5"}, {"SriLanka", "5", "6"} }; String col [] = {"Team", "Selected Players", "Rank"}; DefaultTableModel tableModel = new DefaultTableModel(data, col); JTable table = new JTable(tableModel);Now, use the getModel() to retrieve the value from table cell −Object ob = table.getModel().getValueAt(3, 2); System.out.println("Value = "+ob);The following is an example to retrieve the value from a table cell with TableModel −Examplepackage my; import java.awt.Dimension; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JRootPane; import javax.swing.JScrollPane; import ...
Read MoreHow to disable a Tab in a JTabbedPane Container with Java?
To disable a tab in a JTabbedPane container, use the setEnabledAt() method and set it to false with the index of the tab you want to disable.Let’s first create a JTabbedPane −JTabbedPane tabbedPane = new JTabbedPane();Now, let us disable a tab at index 2 −tabbedPane.setEnabledAt(2, false);The following is an example to disable a tab in a JTabbedPane Container −Examplepackage my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Devices"); JTabbedPane tabbedPane = new JTabbedPane(); JTextArea text = new JTextArea(100, 100); ...
Read MoreHow can we change the default font of the JTabbedPane tabs in Java?
To display the default font of the tabs, you need to use the Font class. Let’s say we created a JTabbedPane in Java −JTabbedPane tabbedPane = new JTabbedPane();Now, set the Font with font face, style and font size −Font font = new Font("Arial", Font.CENTER_BASELINE, 20); tabbedPane.setFont(font);The following is an example to change the default font of the JTabbedPane tabs −package my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Technologies"); JTabbedPane tabbedPane = new JTabbedPane(); JPanel panel1, panel2, panel3, panel4, ...
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