Programming Articles - Page 2700 of 3366

To create a calculator with Java Swings, try the following code −Exampleimport java.awt.Color; import java.awt.Container; import java.awt.FlowLayout; import javax.swing.JFrame; import javax.swing.JLabel; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JTextField; public class SwingDemo extends JFrame implements ActionListener {    JButton one, two, three, four, five, six, seven, eight, nine, num0, add, sub, div, mult, equalto, exit, point, reset;    JTextField textField;    String s = "", ope = "";    int flag = 0;    double total1;    double input1, input2;    void total(double input1, double inout2, String ope) {       String total;       if (ope.equalsIgnoreCase("+")) ... Read More

In this article, we will learn two ways to handle decimal values in Java. First, we will use the BigDecimal class to ensure precision when working with decimals. Then, we will use the DecimalFormat class to format decimal values. Both examples will show how to scale decimal values to three places. Different Approaches to Save Decimal Values The following are the two approaches to save decimal values in Java − Using BigDecimal Using DecimalFormat Save Decimal Values Using BigDecimal for Precision Control The BigDecimal class of java.math package is used for ... Read More

To evaluate mathematical expression in String, use Nashorn JavaScript in Java i.e. scripting. Nashorn invoke dynamics feature, introduced in Java 7 to improve performance.For scripting, use the ScriptEngineManager class for the engine −ScriptEngineManager scriptEngineManager = new ScriptEngineManager(); ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("JavaScript");Now for JavaScript code from string, use eval i.e. execute the script. Here, we are evaluating mathematical expressions in a string −Object ob = scriptEngine.eval("9 + 15 + 30"); System.out.println("Result of evaluating mathematical expressions in String = "+ob);Example Live Demoimport javax.script.ScriptEngine; import javax.script.ScriptEngineManager; public class Main {    public static void main(String[] args) throws Exception {       ScriptEngineManager scriptEngineManager ... Read More

Internet Protocol is currently in the process of moving from version 4 to version 6. This is necessitated because version 4 doesn’t provide enough addresses to handle the increasing number of devices with direct connections to the internet.An IPv4 address is composed of 32 bits, represented into four eight bit groups called as "octets". This is a "dotted decimal" format where each eight-bit octet can have a decimal value 0 to 255.For example: 192.168.1.1IPv4 address with CIDR notation: 192.168.1.1/24 where 24 means first three octets identify the network and last octet identifies node.An IPv6 address is 128 bits long. It ... Read More

Web site owners use the /robots.txt file to give instructions about their site to web robots; this is called The Robots Exclusion Protocol. This file is a simple text-based access control system for computer programs that automatically access web resources. Such programs are called spiders, crawlers, etc. The file specifies the user agent identifier followed by a list of URLs the agent may not access.For example#robots.txt Sitemap: https://example.com/sitemap.xml User-agent: * Disallow: /admin/ Disallow: /downloads/ Disallow: /media/ Disallow: /static/This file is usually put in the top-level directory of your web server.Python's urllib.robotparser module provides RobotFileParser class. It answers questions about whether ... Read More

This module provides a standard interface to break Uniform Resource Locator (URL) strings in components or to combine the components back into a URL string. It also has functions to convert a "relative URL" to an absolute URL given a "base URL."This module supports the following URL schemes -fileftpgopherhdlhttphttpsimapmailtommsnewsnntpprosperorsyncrtsprtspusftpshttpsipsipssnewssvnsvn+sshtelnetwaiswswssurlparse()This function parses a URL into six components, returning a 6-tuple. This corresponds to the general structure of a URL. Each tuple item is a string. The components are not broken up in smaller parts (for example, the network location is a single string), and % escapes are not expanded. The return ... Read More

The HTMLParser class defined in this module provides functionality to parse HTML and XHMTL documents. This class contains handler methods that can identify tags, data, comments and other HTML elements.We have to define a new class that inherits HTMLParser class and submit HTML text using feed() method.from html.parser import HTMLParser class parser(HTMLParser): pass p = parser() p.feed('')We have to override its following methodshandle_starttag(tag, attrs):HTML tags normally are in pairs of starting tag and end tag. For example and . This method is called to handle the start of a tag.Name of the tag converted to lower case. The attrs ... Read More

Function in Python is said to be of higher order. It means that it can be passed as argument to another function and/or can return other function as well. The functools module provides important utilities for such higher order functions.partial() functionThis function returns a callable 'partial' object. The object itself behaves like a function. The partial() function receives another function as argument and freezes some portion of a function’s arguments resulting in a new object with a simplified signature.The built-in int() function converts a number to a decimal integer. Default signature of int() isint(x, base = 10)The partial() function can ... Read More

What is a Copy Operation in Python? Copying in Python refers to the process of creating a duplicate of existing data. The simplest way to create a reference to an object is by using the assignment operator (=), but this does not create an actual copy—it only makes the new variable point to the same object in memory. To create an independent copy, Python provides two methods: shallow copy and deep copy, which can be achieved using the copy module. The Assignment operator doesn't create a new object; instead, it binds a new variable to the same memory address ... Read More

Performing sort operations after every insertion on a long list may be expensive in terms of time consumed by processor. The bisect module ensures that the list remains automatically sorted after insertion. For this purpose, it uses bisection algorithm. The module has following functions:bisect_left()This method locates insertion point for a given element in the list to maintain sorted order. If it is already present in the list, the insertion point will be before (to the left of) any existing entries. The return value caan be used as the first parameter to list.insert()bisect_right()This method is similar to bisect_left(), but returns an ... Read More