Tutorial by Examples: di

Adding a Gesture recognizer in the Interface Builder

Drag a gesture recognizer from the object library onto your view. Control drag from the gesture in the Document Outline to your View Controller code in order to make an Outlet and an Action. Notes This example comes from this fuller sample project demonstrating gesture recognizers.

iOS • UIGestureRecognizer

How to edit jar files with ASM

Firstly the classes from the jar need to be loaded. We'll use three methods for this process: loadClasses(File) readJar(JarFile, JarEntry, Map) getNode(byte[]) Map<String, ClassNode> loadClasses(File jarFile) throws IOException { Map<String, ClassNode> classes = new HashMap&...

Java Language • Bytecode Modification

Disabling Blueprint Routes

Global basis: Blueprint API configuration is defined in /config/blueprint.js file. You can enable or disable all three types of blueprint routes for all controllers from there. As example, if you want to disable blueprint shortcut routes for all of your controllers but want to keep both acti...

sails.js • Blueprint API

Uploading files with HTTP PUT

PHP provides support for the HTTP PUT method used by some clients to store files on a server. PUT requests are much simpler than a file upload using POST requests and they look something like this: PUT /path/filename.html HTTP/1.1 Into your PHP code you would then do something like this: <?p...

PHP • Reading Request Data

Read from stdin

Python programs can read from unix pipelines. Here is a simple example how to read from stdin: import sys for line in sys.stdin: print(line) Be aware that sys.stdin is a stream. It means that the for-loop will only terminate when the stream has ended. You can now pipe the output of anot...

Python Language • Basic Input and Output

Displaying Debug Information

The current frame rate (in FPS, Frames Per Second) and total number of SKNodes in the scene (nodeCount, each sprite is an SKNode but other objects in the scene are also SKNodes) can be shown in the bottom right hand corner of the view. These can be useful when turned on (set to true) for debugging ...

sprite-kit • SKView

Try-finally nested inside try-except

A try-finally block may be nested inside a try-except block. try AcquireResources; try UseResource; finally ReleaseResource; end; except on E: EResourceUsageError do begin HandleResourceErrors; end; end; If an exception occurs inside UseResource, then execution...

Embarcadero Delphi • Use of try, except, and finally

Try-except nested inside try-finally

A try-except block may be nested inside a try-finally block. AcquireResource; try UseResource1; try UseResource2; except on E: EResourceUsageError do begin HandleResourceErrors; end; end; UseResource3; finally ReleaseResource; end; If an EResourceUsageE...

Embarcadero Delphi • Use of try, except, and finally

Displaying and handling alerts

One Button Swift class ViewController: UIViewController { @IBAction func showAlertButtonTapped(sender: UIButton) { // create the alert let alert = UIAlertController(title: "My Title", message: "This is my message.", preferredStyle: UIAlertCo...

iOS • UIAlertController

Clustered index

When using clustered index, the rows of the table are sorted by the column to which the clustered index is applied. Therefore, there can be only one clustered index on the table because you can't order the table by two different columns. Generally, it is best to use clustered index when performing ...

SQL • Indexes

Non clustered index

Nonclustered indexes are stored separately from the table. Each index in this structure contains a pointer to the row in the table which it represents. This pointers are called a row locators. The structure of the row locator depends on whether the data pages are stored in a heap or a clustered tab...

SQL • Indexes

Testing and installating Coq

Testing without installing For new users who wish to start testing Coq without installing it on their machine, there is an online IDE called JsCoq (presentation here). The package sub-window allows testing various well-known additional packages. Installation The download page contains installers ...

coq • Getting started with coq

Embedding into HTML

There are three possibilities to insert Elm code into a existing HTML page. Embed into the body tag Supposing you have compiled the Hello World example into elm.js file, you can let Elm take over the <body> tag like so: <!DOCTYPE html> <html> <body> <scri...

Elm Language • Getting started with Elm Language

Adding eslint to your Meteor project

We'll use the popular eslint-config-airbnb as a starter as well as Meteor specific rules using eslint-import-resolver-meteor. We also need to install babel-parser to lint Meteor enabled ES7 features such as async/await. cd my-project npm install --save-dev eslint-config-airbnb eslint-plugin-impor...

meteor • ESLint

Printing the Difference of the Values of two Pointers to an Object

Subtracting the values of two pointers to an object results in a signed integer *1. So it would be printed using at least the d conversion specifier. To make sure there is a type being wide enough to hold such a "pointer-difference", since C99 <stddef.h> defines the type ptrdiff_t. ...

C Language • Formatted Input/Output

Getting started and finding help

The package's official wiki has some essential materials: As a new user, you will want to check out the vignettes, FAQ and cheat sheet. Before asking a question -- here on StackOverflow or anywhere else -- please read the support page. For help on individual functions, the syntax is h...

data.table • Getting started with data.table

Loading Model

Syntax - $this->load->model('model_name'); Practice - $this->load->model('home_model'); If you would like your model assigned to a different object name you can specify it via the second parameter of the loading method: Syntax - $this->load->model('model_name', 'foobar'); ...

codeigniter • Using Model in codeigniter

Prefer local variables to globals, attributes, and indexed values

Javascript engines first look for variables within the local scope before extending their search to larger scopes. If the variable is an indexed value in an array, or an attribute in an associative array, it will first look for the parent array before it finds the contents. This has implications wh...

JavaScript • Performance Tips

Editing index.ios.js or index.android.js

Open index.ios.js or index.android.js and delete everything between the <View> </View>. After that, write <Text> Hello World! </Text> and run the emulator. You should see Hello World! written on the screen! Congrats! You've successfully written your first Hello World!

react-native • Hello World

Editing values

# example data DT = as.data.table(mtcars, keep.rownames = TRUE) Editing a column Use the := operator inside j to create new columns or modify existing ones: DT[, mpg_sq := mpg^2] Editing on a subset of rows Use the i argument to subset to rows "where" edits should be made: DT[1:...

data.table • Adding and modifying columns