Tutorial by Examples: r

One big problem is that valuable named routes is not supported by Express out of the box. Solution is to install supported third-party package, for example express-reverse: npm install express-reverse Plug it in your project: var app = require('express')(); require('express-reverse')(app); ...

The standard (17.6.4.2.1/1) generally forbids extending the std namespace: The behavior of a C++ program is undefined if it adds declarations or definitions to namespace std or to a namespace within namespace std unless otherwise specified. The same goes for posix (17.6.4.2.2/1): The behavi...

To find if a string starts with a pattern, the start_with? method comes in handy str = "zebras are cool" str.start_with?("zebras") => true You can also check the position of the pattern with index str = "zebras are cool" str.index("zebras").zero...

To find if a string ends with a pattern, the end_with? method comes in handy str = "I like pineapples" str.end_with?("pineaaples") => false

In Ruby, strings can be left-justified, right-justified or centered To left-justify string, use the ljust method. This takes in two parameters, an integer representing the number of characters of the new string and a string, representing the pattern to be filled. If the integer is greater than th...

An array is a data structure that stores values of same data type. In Python, this is the main difference between arrays and lists. While python lists can contain values corresponding to different data types, arrays in python can only contain values corresponding to same data type. In this tutorial...

Intent: Separate the construction of a complex object from its representation so that the same construction process can create different representations Builder pattern is useful when you have few mandatory attributes and many optional attributes to construct a object. To create an object with dif...

Often you will want to perform asynchronous operations in parallel. There is direct syntax that supports this in the async/await proposal, but since await will wait for a promise, you can wrap multiple promises together in Promise.all to wait for them: // Not in parallel async function getFriend...

entry = tk.Entry(parent, width=10) entry.insert(0, "Hello, World!")

The value of an entry widget can be obtained with the get method of the widget: name_entry = tk.Entry(parent) ... name = name_entry.get() Optionally, you may associate an instance of a StringVar, and retrieve the value from the StringVar rather than from the widget: name_var = tk.StringVar() ...

// A simple class hierarchy that uses the visitor to add functionality. // class VehicleVisitor; class Vehicle { public: // To implement the visitor pattern // The class simply needs to implement the accept method // That takes a reference to a visitor object tha...

The visitor Pattern can be used to traverse structures. class GraphVisitor; class Graph { public: class Node { using Link = std::set<Node>::iterator; std::set<Link> linkTo; public: void accept(GraphVisito...

Since Java lambdas are closures, they can "capture" the values of variables in the enclosing lexical scope. While not all lambdas capture anything -- simple lambdas like s -> s.length() capture nothing and are called stateless -- capturing lambdas require a temporary object to hold the...

Modules can be required without using relative paths by putting them in a special directory called node_modules. For example, to require a module called foo from a file index.js, you can use the following directory structure: index.js \- node_modules \- foo |- foo.js \- package.json ...

<?php use Symfony\Bundle\FrameworkBundle\Controller\Controller; use Symfony\Component\HttpFoundation\Request; class TestController extends Controller { //Inject Request HTTP Component in your function then able to exploit it public function myFunctionAction(Request $request) {...

Objective-C UILabel *label = [[UILabel alloc] init]; label.highlighted = YES; label.highlightedTextColor = [UIColor redColor]; Swift let label = UILabel() label.highlighted = true label.highlightedTextColor = UIColor.redColor() Swift 3 let label = UILabel() label.isHighlighted = true ...

ngHref is used instead of href attribute, if we have a angular expressions inside href value. The ngHref directive overrides the original href attribute of an html tag using href attribute such as tag, tag etc. The ngHref directive makes sure the link is not broken even if the user clicks the lin...

Usage: $ nodetool repair [-h | -p | -pw | -u] <flags> [ -- keyspace_name [table_name]] Default Repair Option $ nodetool repair This command will repair the current node's primary token range (i.e. range which it owns) along with the replicas of other token ranges it has in all tables a...

Apps Script: //Triggered when the page is navigated to, serves up HTML function doGet(){ var template = HtmlService.createTemplateFromFile('index'); return template.evaluate() .setTitle('Example App') .setSandboxMode(HtmlService.SandboxMode.IFRAME); } //Called from the cli...

System.Obsolete is an attribute that is used to mark a type or a member that has a better version, and thus should not be used. [Obsolete("This class is obsolete. Use SomeOtherClass instead.")] class SomeClass { // } In case the class above is used, the compiler will give the w...