Tutorial by Examples: d

Pseudo-elements are added to selectors but instead of describing a special state, they allow you to style certain parts of a document. The content attribute is required for pseudo-elements to render; however, the attribute can have an empty value (e.g. content: ""). div::after { conte...

What is recursion: In general, recursion is when a function invokes itself, either directly or indirectly. For example: // This method calls itself "infinitely" public void useless() { useless(); // method calls itself (directly) } Conditions for applying recursion to a probl...

Swift let mapView = MKMapView(frame: CGRect(x: 0, y: 0, width: 320, height: 500)) It's recommended to store the mapView as a property of the containing ViewController since you might want to access it in more complex implementations. Objective C self.map = [[MKMapView alloc]initWithFrame:CGRec...

Just like all programming language, Matlab is designed to read and write in a large variety of formats. The native library supports a large number of Text,Image,Video,Audio,Data formats with more formats included in each version update - check here to see the full list of supported file formats and ...

To make a rounded UIView, specify a cornerRadius for the view's layer. This also applies any class which inherits from UIView, such as UIImageView. Programmatically Swift Code someImageView.layoutIfNeeded() someImageView.clipsToBounds = true someImageView.layer.cornerRadius = 10 Objective-C...

In this example, we will look at a method for returning the last non-empty row in a column for a data set. This method will work regardless of empty regions within the data set. However caution should be used if merged cells are involved, as the End method will be "stopped" against a mer...

Any Fortran program has to include end as last statement. Therefore, the simplest Fortran program looks like this: end Here are some examples of "hello, world" programs: print *, "Hello, world" end With write statement: write(*,*) "Hello, world" end For c...

The double-negation !! is not a distinct JavaScript operator nor a special syntax but rather just a sequence of two negations. It is used to convert the value of any type to its appropriate true or false Boolean value depending on whether it is truthy or falsy. !!1 // true !!0 ...

All Java exceptions are instances of classes in the Exception class hierarchy. This can be represented as follows: java.lang.Throwable - This is the base class for all exception classes. Its methods and constructors implement a range of functionality common to all exceptions. java.lang.Excep...

A function defined as async is a function that can perform asynchronous actions but still look synchronous. The way it's done is using the await keyword to defer the function while it waits for a Promise to resolve or reject. Note: Async functions are a Stage 4 ("Finished") proposal on tr...

x = (1, 2, 3) x[0] # 1 x[1] # 2 x[2] # 3 x[3] # IndexError: tuple index out of range Indexing with negative numbers will start from the last element as -1: x[-1] # 3 x[-2] # 2 x[-3] # 1 x[-4] # IndexError: tuple index out of range Indexing a range of elements print(x[:-1]) # (1,...

A context manager is an object that is notified when a context (a block of code) starts and ends. You commonly use one with the with statement. It takes care of the notifying. For example, file objects are context managers. When a context ends, the file object is closed automatically: open_file = ...

In Python 2, an iterator can be traversed by using a method called next on the iterator itself: Python 2.x2.3 g = (i for i in range(0, 3)) g.next() # Yields 0 g.next() # Yields 1 g.next() # Yields 2 In Python 3 the .next method has been renamed to .__next__, acknowledging its “magic” ro...

SELECT * FROM Employees ORDER BY LName This statement will return all the columns from the table Employees. IdFNameLNamePhoneNumber2JohnJohnson24681012141JamesSmith12345678903MichaelWilliams1357911131 SELECT * FROM Employees ORDER BY LName DESC Or SELECT * FROM Employees ORDER BY LName ASC...

Windows Environment Install XAMPP or WAMP Download and Unzip the package from Codeigniter.com Extract all the document in the server space (htdocs or www directory) Mac Environment Install MAMP Download and Unzip the package from Codeigniter.com Extract all the document in the server sp...

The null coalescing operator makes it easy to ensure that a method that may return null will fall back to a default value. Without the null coalescing operator: string name = GetName(); if (name == null) name = "Unknown!"; With the null coalescing operator: string name = GetN...

Running the latest Liferay CE is straightforward: Go to https://www.liferay.com/downloads. Choose a bundle among the ones listed. For beginners, the Tomcat bundle is a good choice. Click in "Download." Unzip the download package whenever you find fit. The unzipped directory will...

With promises: function doTheThing() { return doOneThing() .then(doAnother) .then(doSomeMore) .catch(handleErrors) } With async functions: async function doTheThing() { try { const one = await doOneThing(); const another = await doAnother(...

You can use a column's number (where the leftmost column is '1') to indicate which column to base the sort on, instead of describing the column by its name. Pro: If you think it's likely you might change column names later, doing so won't break this code. Con: This will generally reduce readabilit...

Requirements: Protractor requires the following dependencies to be installed prior to installation: Java JDK 1.7 or higher Node.js v4 or higher Installation: Download and install Node.js from this URL: https://nodejs.org/en/ To see if the Node.js installation is successfull, you can go an...