Tutorial by Examples: all

Cocoa is Apple's API to develop apps for macOS, formerly known as OS X. Cocoa is a container framework, and contains three sub-frameworks. Foundation AppKit CoreData Cocoa Touch is Apple's version of Cocoa to develop apps for iOS, watchOS and tvOS. Cocoa Touch contains the same sub-framewo...

Calling an instance method: [classInstance hello]; @interface Sample -(void)hello; // exposing the class Instance method @end @implementation Sample -(void)hello{ NSLog(@"hello"); } @end Calling an instance method on the current instance: [self hell...

Unlike C++ in C# you can call a virtual method from class constructor (OK, you can also in C++ but behavior at first is surprising). For example: abstract class Base { protected Base() { _obj = CreateAnother(); } protected virtual AnotherBase CreateAnother() { ...

To add a method to a button, first create an action method: Objective-C -(void)someButtonAction:(id)sender { // sender is the object that was tapped, in this case its the button. NSLog(@"Button is tapped"); } Swift func someButtonAction() { print("Button is tapped...

TRUNCATE TABLE Employee; Using truncate table is often better then using DELETE TABLE as it ignores all the indexes and triggers and just removes everything. Delete table is a row based operation this means that each row is deleted. Truncate table is a data page operation the entire data page is...

DELETE FROM table_name ; This will delete everything, all rows from the table. It is the most basic example of the syntax. It also shows that DELETE statements should really be used with extra care as they may empty a table, if the WHERE clause is omitted.

Statement-level parallel hints are the easiest: SELECT /*+ PARALLEL(8) */ first_name, last_name FROM employee emp; Object-level parallel hints give more control but are more prone to errors; developers often forget to use the alias instead of the object name, or they forget to include some objec...

Post::find()->all(); // SELECT * FROM post or the shorthand (Returns an active record model instance by a primary key or an array of column values.) Post::findAll(condition); returns an array of ActiveRecord instances. Find All with where Condition $model = User::find() ->w...

It is worth noting that in swift, unlike other languages people are familiar with, there is an implicit break at the end of each case statement. In order to follow through to the next case (i.e. have multiple cases execute) you need to use fallthrough statement. switch(value) { case 'one': //...

This guide assumes you already have Ruby installed. If you're using Ruby < 1.9 you'll have to manually install RubyGems as it won't be included natively. To install a ruby gem, enter the command: gem install [gemname] If you are working on a project with a list of gem dependencies, then the...

In Python 3.x all classes are new-style classes; when defining a new class python implicitly makes it inherit from object. As such, specifying object in a class definition is a completely optional: Python 3.x3.0 class X: pass class Y(object): pass Both of these classes now contain object in ...

Ansible can be installed on CentOS or other Red Hat based systems. Firstly you should install the prerequisites: sudo yum -y update sudo yum -y install gcc libffi-devel openssl-devel python-pip python-devel then install Ansible with pip: sudo pip install ansible I can recommend for you to u...

Match any: Must match at least one string. In this example the product type must be either 'electronics', 'books', or 'video'. SELECT * FROM purchase_table WHERE product_type LIKE ANY ('electronics', 'books', 'video'); Match all (must meet all requirements). In this example both 'united...

The foreach package brings the power of parallel processing to R. But before you want to use multi core CPUs you have to assign a multi core cluster. The doSNOW package is one possibility. A simple use of the foreach loop is to calculate the sum of the square root and the square of all numbers from...

Installing linq-to-sql: Right-click the App_Code folder and then click Add New Item. The Add New Item dialog box is displayed. Under Visual Studio installed templates, select the LINQ to SQL Classes template and rename the file Tasks.dbml. Click Add. OR: Under VS2102, in your solution explorer, r...

CHICKEN is a Scheme interpreter and compiler with its own extension module system called "eggs". It is capable of compiling Scheme to native code by first compiling Scheme to C. Installing Debian or Ubuntu or other derived distros: sudo apt-get install chicken-bin Fedora / RHEL / Ce...

Express JS is the goto framework for developing Web Applications, APIs and almost any kind of Backend using Node. To install express, all you have to do is run the npm command npm install express --save And you're done. To create and run a new express server create a file app.js and add this ...

Detailed instructions on getting mapbox set up or installed.

This example demonstrates that HTTP is a text-based Internet communications protocol, and shows a basic HTTP request and the corresponding HTTP response. You can use Telnet to manually send a minimal HTTP request from the command line, as follows. Start a Telnet session to the web server www.e...

FlashDevelop is a multi-platform open source IDE created in 2005 for Flash developers. With no cost, it's a very popular way to get started developing with AS3. To Install FlashDevelop: Download The Installation File and run the installer Once installation is complete, run FlashDevelop. On the ...