Tutorial by Examples: v

To connect using java.sql.DriverManager you need a JDBC url to connect to your database. JDBC urls are database specific, but they are all of the form jdbc:<subprotocol>:<subname> Where <subprotocol> identifies the driver or database (for example postgresql, mysql, firebirdsql,...

Consider the following component with one input myInput and an internal value called someInternalValue. Both of them are used in a component's template. import {Component, Input} from '@angular/core'; @Component({ template:` <div> <p>{{myInput}}</p> <p>{...

trait HelloWorld { public function sayHello() { echo 'Hello World!'; } } // Change visibility of sayHello class MyClass1 { use HelloWorld { sayHello as protected; } } // Alias method with changed visibility // sayHello visibility not changed class MyClass2 { u...

Consider this broken snippet: def foo bar = [1, 2, 3, 4].map do |x| return 0 if x.even? x end puts 'baz' bar end foo # => 0 One might expect return to yield a value for map's array of block results. So the return value of foo would be [1, 0, 3, 0]. Instead, return retu...

Type variables are uncapitalized names in type-signatures. Unlike their capitalized counterparts, such as Int and String, they do not represent a single type, but rather, any type. They are used to write generic functions that can operate on any type or types, and are particularly useful for writing...

Aliasing types cuts down on boilerplate and enhances readability, but it is no more type-safe than the aliased type itself is. Consider the following: type alias Email = String type alias Name = String someEmail = "[email protected]" someName = "Benedict" sendEmail ...

A common task is to convert all columns of a data.frame to character class for ease of manipulation, such as in the cases of sending data.frames to a RDBMS or merging data.frames containing factors where levels may differ between input data.frames. The best time to do this is when the data is read ...

Each of Laravel's queue drivers are configured from the config/queue.php file. A queue driver is the handler for managing how to run a queued job, identifying whether the jobs succeeded or failed, and trying the job again if configured to do so. Out of the box, Laravel supports the following queue ...

Through the use of event types you can easily reduce code bloat that often occurs when defining events for many objects on stage by filtering events in 1 function rather than defining many event handling functions. Imagine we have 10 objects on stage named object1, object2 ... object10 You could d...

Sometimes it's a good idea to further secure your publishes by requiring a user login. Here is how you achieve this via Meteor. import { Recipes } from '../imports/api/recipes.js'; import { Meteor } from 'meteor/meteor'; Meteor.publish('recipes', function() { if(this.userId) { return Re...

Hashes can be freely converted to and from arrays. Converting a hash of key/value pairs into an array will produce an array containing nested arrays for pair: { :a => 1, :b => 2 }.to_a # => [[:a, 1], [:b, 2]] In the opposite direction a Hash can be created from an array of the same form...

Firebase Authentication allows the users of your app to sign-in with social providers or their email+password. But what if you want to store additional information about a user, beyond what Firebase Authentication allows you to specify? Or what if you want to display a list of the users in your app...

The following assumes you will use kdiff3 for file diffing and although not essential it is a good idea. C:\> choco install kdiff3 Git can be installed first so you can state any parameters you wish. Here all the Unix tools are also installed and 'NoAutoCrlf' means checkout as is, commit as i...

Stashing takes the dirty state of your working directory – that is, your modified tracked files and staged changes – and saves it on a stack of unfinished changes that you can reapply at any time. Stashing only modified files: Suppose you don't want to stash the staged files and only stash the mod...

If you created an empty project, or you still don't have mvc configured in your application, you can add dependency: "Microsoft.AspNetCore.Mvc": "1.0.1" To your project.json file under "dependencies". And register MVC middleware in your Startup class: public void ...

Meteor Tool To check the installed version of the Meteor tool, just run the following command outside of any Meteor projects: meteor --version To get a list of all official (recommended) Meteor releases, run: meteor show METEOR Meteor Projects If you want to check the project version of Me...

You often find yourself in a situation where you need to find a variables corresponding value, and collections got you covered. In the example below we got three different locales in an array with a corresponding calling code assigned. We want to be able to provide a locale and in return get the as...

valgrind ./my-program arg1 arg2 < test-input This will run your program and produce a report of any allocations and de-allocations it did. It will also warn you about common errors like using uninitialized memory, dereferencing pointers to strange places, writing off the end of blocks allocate...

wikipedia definition: Command pattern is a behavioral design pattern in which an object is used to encapsulate all information needed to perform an action or trigger an event at a later time UML diagram from dofactory: Basic components and workflow: Command declares an interface for abst...

ClientContext clientContext = new ClientContext(siteUrl); Web oWebsite = clientContext.Web; clientContext.Load(oWebsite); clientContext.ExecuteQuery(); Console.WriteLine("Title: {0} Description: {1}", oWebsite.Title, oWebsite.Description);