Tutorial by Examples: di

When you extend a class, you can override methods that the inherited class defines using the override keyword: public class Example { public function test():void { trace('It works!'); } } public class AnotherExample extends Example { public override function test():void ...

If you have your data stored in a list and you want to convert this list to a data frame the do.call function is an easy way to achieve this. However, it is important that all list elements have the same length in order to prevent unintended recycling of values. dataList <- list(1:3,4:6,7:9) ...

HTML5 provides a new standard for embedding an audio file on a web page. You can embed an audio file to a page using the <audio> element: <audio controls> <source src="file.mp3" type="audio/mpeg"> Your browser does not support the audio element. </audi...

OnClick Listener: @OnClick(R.id.login) public void login(View view) { // Additional logic } All arguments to the listener method are optional: @OnClick(R.id.login) public void login() { // Additional logic } Specific type will be automatically casted: @OnClick(R.id.submit) publi...

Fragments have a different view lifecycle than activities. When binding a fragment in onCreateView, set the views to null in onDestroyView. Butter Knife returns an Unbinder instance when you call bind to do this for you. Call its unbind method in the appropriate lifecycle callback. An example: pub...

CSV(Comma Separated Values) is a simple file format used to store tabular data, such as a spreadsheet. This is a minimal example of how to write & read data in Python. Writing data to a CSV file: import csv data = [["Ravi", "9", "550"], ["Joe", "8...

Open the Settings or Preferences dialog: On Windows or Linux, select File > Settings from the main menu. On Mac OSX, select Android Studio > Preferences from the main menu. Navigate to Build, Execution, Deployment > Compiler. In the text field next to Command-line Options, enter...

If you are familiar with jQuery and Sizzle syntax, d3 selections should not be much different. d3 mimics the W3C Selectors API to make interacting with elements easier. For a basic example, to select all <p> and add a change to each of them: d3.selectAll('p') .attr('class','textClass') ...

C++11 In the header file: // widget.h #include <memory> // std::unique_ptr #include <experimental/propagate_const> class Widget { public: Widget(); ~Widget(); void DoSomething(); private: // the pImpl idiom is named after the typ...

You can redirect the debug output to a text file by adding a TextWriterTraceListener to the Debug.Listeners collection. public static void Main(string[] args) { TextWriterTraceListener myWriter = new TextWriterTraceListener(@"debug.txt"); Debug.Listeners.Add(myWriter); Deb...

Sometimes, it's not possible to list the number of parameters a function could need. Consider a sum function: func sum(_ a: Int, _ b: Int) -> Int { return a + b } This works fine for finding the sum of two numbers, but for finding the sum of three we'd have to write another function: f...

If you want to display to your users meaningful errors instead of simple "sorry, something went wrong", Rails has a nice utility for the purpose. Open the file app/controllers/application_controller.rb and you should find something like this: class ApplicationController < ActionContro...

The border-radius property allows you to change the shape of the basic box model. Every corner of an element can have up to two values, for the vertical and horizontal radius of that corner (for a maximum of 8 values). The first set of values defines the horizontal radius. The optional second ...

<PROJECT_ROOT>\app\build.gradle is specific for app module. <PROJECT_ROOT>\build.gradle is a "Top-level build file" where you can add configuration options common to all sub-projects/modules. If you use another module in your project, as a local library you would have another...

Each pair in the dictionary is an instance of KeyValuePair with the same type parameters as the Dictionary. When you loop through the dictionary with For Each, each iteration will give you one of the Key-Value Pairs stored in the dictionary. For Each kvp As KeyValuePair(Of String, String) In curren...

Dim extensions As New Dictionary(Of String, String) _ from { { "txt", "notepad" }, { "bmp", "paint" }, { "doc", "winword" } } This creates a dictionary and immediately fills it with three KeyValuePairs. You can also add new val...

Dictionaries are implemented in a Dict core library. A dictionary mapping unique keys to values. The keys can be any comparable type. This includes Int, Float, Time, Char, String, and tuples or lists of comparable types. Insert, remove, and query operations all take O(log n) time. Unlike Tu...

Get width and height: var width = $('#target-element').innerWidth(); var height = $('#target-element').innerHeight(); Set width and height: $('#target-element').innerWidth(50); $('#target-element').innerHeight(100);

Get width and height (excluding margin): var width = $('#target-element').outerWidth(); var height = $('#target-element').outerHeight(); Get width and height (including margin): var width = $('#target-element').outerWidth(true); var height = $('#target-element').outerHeight(true); Set widt...

From the official documentation: Gradle. dependencies { compile "com.squareup.picasso:picasso:2.5.2" } Maven: <dependency> <groupId>com.squareup.picasso</groupId> <artifactId>picasso</artifactId> <version>2.5.2</version> </dep...