Tutorial by Examples: g

Note: Everything below applies to the str.format method, as well as the format function. In the text below, the two are interchangeable. For every value which is passed to the format function, Python looks for a __format__ method for that argument. Your own custom class can therefore have th...

// RawRepresentable has an associatedType RawValue. // For this struct, we will make the compiler infer the type // by implementing the rawValue variable with a type of String // // Compiler infers RawValue = String without needing typealias // struct NotificationName: RawRepresentable { ...

Select the .xcdatamodeld file. You will notice you have no entities. You will have to create one yourself. At the bottom of Xcode you will notice a button that says "Add Entity" click it and you will have a new entity for you to work with on the project. In this step there are ...

With Gson, you can read JSON dataset and map them to a custom class MyClass. Since Gson is not serializable, each executor needs its own Gson object. Also, MyClass must be serializable in order to pass it between executors. Note that the file(s) that is offered as a json file is not a typical JSON...

Pattern matching allows to deconstruct complex values and it is by no way limited to the “outer most” level of the representation of a value. To illustrate this, we implement the function transforming a boolean expression into a boolean expression where all negations are only on atoms, the so calle...

Pattern matching can be used to deconstruct records. We illustrate this with a record type representing locations in a text file, e.g. the source code of a program. type location = { filename : string; line: int; column: int; offset: int; } A value x of type location can be deconstr...

The List.fold_left and List.fold_right functions are higher-order functions that implement the outer logic of list aggregation. Aggregating a list, sometimes also referred to as reducing a list, means computing a value derived from the sequential inspection of all items in that list. The documenta...

final TextView mTextView = (TextView) findViewById(R.id.text); ... // Instantiate the RequestQueue. RequestQueue queue = Volley.newRequestQueue(this); String url ="http://www.google.com"; // Request a string response from the provided URL. StringRequest stringRequest = new String...

There are several additional attributes that the Volley NetworkImageView adds to the standard ImageView. However, these attributes can only be set in code. The following is an example of how to make an extension class that will pick up the attributes from your XML layout file and apply them to the N...

In Elm, reducing functions are called "folds", and there are two standard methods to "fold" values up: from the left, foldl, and from the right, foldr. > List.foldl (+) 0 [1,2,3] 6 : number The arguments to foldl and foldr are: reducing function: newValue -> accumul...

A reference to an option &Option<T> cannot be unwrapped if the type T is not copyable. The solution is to change the option to &Option<&T> using as_ref(). Rust forbids transferring of ownership of objects while the objects are borrowed. When the Option itself is borrowed (&a...

To remove a specific item from the browser Storage (the opposite of setItem) use removeItem localStorage.removeItem("greet"); Example: localStorage.setItem("greet", "hi"); localStorage.removeItem("greet"); console.log( localStorage.getItem("greet...

localStorage, sessionStorage are JavaScript Objects and you can treat them as such. Instead of using Storage Methods like .getItem(), .setItem(), etc… here's a simpler alternative: // Set localStorage.greet = "Hi!"; // Same as: window.localStorage.setItem("greet", "Hi!&qu...

Type casting is done with either the as operator: var chair:Chair = furniture as Chair; Or by wrapping the value in Type(): var chair:Chair = Chair(furniture); If the cast fails with as, the result of that cast is null. If the cast fails by wrapping in Type(), a TypeError is thrown.

You can tell the compiler the type of a value by annotating it with :Type: var value:int = 10; // A property "value" of type "int". Function parameters and return types can also be annotated: // This function accepts two ints and returns an int. function sum(a:int, b:int):i...

You can use the is operator to validate whether a value is of a certain type: var sprite:Sprite = new Sprite(); trace(sprite is Sprite); // true trace(sprite is DisplayObject); // true, Sprite inherits DisplayObject trace(sprite is IBitmapDrawable); // true, DisplayObject implements IBitmapDra...

The C++ approach - new and delete In a language like C++, the application program is responsible for managing the memory used by dynamically allocated memory. When an object is created in the C++ heap using the new operator, there needs to be a corresponding use of the delete operator to dispose o...

3 You can use rem defined by the font-size of your html tag to style elements by setting their font-size to a value of rem and use em inside the element to create elements that scale with your global font-size. HTML: <input type="button" value="Button"> <input type=...

localStorage.length property returns an integer number indicating the number of elements in the localStorage Example: Set Items localStorage.setItem('StackOverflow', 'Documentation'); localStorage.setItem('font', 'Helvetica'); localStorage.setItem('image', 'sprite.svg'); Get length localSto...

Holy Grail layout is a layout with a fixed height header and footer, and a center with 3 columns. The 3 columns include a fixed width sidenav, a fluid center, and a column for other content like ads (the fluid center appears first in the markup). CSS Flexbox can be used to achieve this with a very s...