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Anonymous class is an inner class without a name, which means that we can declare and instantiate class at the same time. A lambda expression is a short form for writing an anonymous class. By using a lambda expression, we can declare methods without any name.Anonymous class vs Lambda ExpressionAn anonymous class object generates a separate class file after compilation that increases the size of a jar file while a lambda expression is converted into a private method. It uses invokedynamic bytecode instruction to bind this method dynamically, which saves time and memory.We use this keyword to represent the current class in lambda expression while in the ... Read More
When running python programs, we need to use datasets for data analysis. Python has various modules which help us in importing the external data in various file formats to a python program. In this example we will see how to import data of various formats to a python program.Import csv fileThe csv module enables us to read each of the row in the file using a comma as a delimiter. We first open the file in read only mode and then assign the delimiter. Finally use a for loop to read each row from the csv file.Exampleimport csv with ... Read More
A lambda expression is an anonymous function without having any name and does not belong to any class that means it is a block of code that can be passed around to execute.Syntax(parameter-list) -> {body}We can implement a lambda expression without creating an anonymous inner class in the below program. For the button's ActionListener interface, we need to override one abstract method addActionListener() and implement the block of code using the lambda expression.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class LambdaExpressionButtonTest extends JFrame { private JButton btn; public LambdaExpressionButtonTest() { btn = new JButton("Click on the button"); ... Read More
Yes, any lambda expression is an object in Java. It is an instance of a functional interface. We have assigned a lambda expression to any variable and pass it like any other object.Syntax(parameters) -> expression or (parameters) -> { statements; }In the below example, how a lambda expression has assigned to a variable and how it can be invoked.Example@FunctionalInterface interface ComparatorTask { public boolean compare(int t1, int t2); } public class LambdaObjectTest { public static void main(String[] args) { ComparatorTask ctask = (int t1, int t2) -> {return t1 ... Read More
Python can be used to access webpages as well as post content to the webpages. There are various modules like httplib, urllib, httplib2 etc but the requests module is simplest and can be used to write simpler yet powerful programs involving GET and POST methods.GET methodThe GET method is part of the python requests module which is used to obtain data from a web URL. In the below example we reach out to our own website and find out various responses through the get method. We get the encoding, response time and also the header and part of the body.Example Live ... Read More
Python can also be used to create computer games. In this article we will see how the ball catching game can be created using python. In this game a ball keeps falling from the top of a canvas window and a bar is present at the bottom of the window. Two buttons are provided to move the bar in the left and right direction. Using mouse button presss we move the bar at the bottom to catch the falling ball. At different times the ball falls from different positions .ApproachThe approach to build the game is described in the following ... Read More
In python tkinter is a GUI library that can be used for various GUI programming. Such applications are useful to build desktop applications. In this article we will see one aspect of the GUI programming called Binding functions. This is about binding events to functions and methods so that when the event occurs that specific function is executed.Binding keyboard eventIn the below example we bind the press of any key from the keyboard with a function that gets executed. Once the Tkinter GUI window is open, we can press any key in the keyboard and we get a message that ... Read More
We may have a need to associate a given value with each and every element of a list. For example − there are the name of the days and we want to attach the word day as a suffix in them. Such scenarios can be handled in the following ways.With itertools.repeatWe can use the repeat method from itertools module so that the same value is used again and again when paired with the values from the given list using the zip function.Example Live Demofrom itertools import repeat listA = ['Sun', 'Mon', 'Tues'] val = 'day' print ("The Given list : ... Read More
There are different scoping rules for lambda expression in Java. In lambda expressions, this and super keywords are lexically scoped means that this keyword refers to the object of the enclosing type and the super keyword refers to the enclosing superclass. In the case of an anonymous class, they are relative to the anonymous class itself. Similarly, local variables declared in lambda expression conflicts with variables declared in the enclosing class. In the case of an anonymous class, they are allowed to shadow variables in the enclosing class.Example@FunctionalInterface interface TestInterface { int calculate(int x, int y); } class Test { public ... Read More
The lambda expressions are easy and contain three parts like parameters (method arguments), arrow operator (->) and expressions (method body). The lambda expressions can be categorized into three types: no parameter lambda expressions, single parameter lambda expressions and multiple parameters lambda expressions.Lambda Expression with no parameterWe need to create no parameter lambda expression then start the expression with empty parenthesis.Syntax() -> { //Body of no parameter lambda }Example(no parameter Lambda)import java.util.function.*; import java.util.Random; public class LambdaExpression1 { public static void main(String args[]) { NumberUtil num = new NumberUtil(); int randVal = num.getRandomValue( ... Read More