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By default, Interface Builder doesn't accept the CGColor datatype, so to allow adding a CGColor using user defined attributes in interface builder; one may want to use an extension like this: Swift Extension : extension CALayer { func borderUIColor() -> UIColor? { return borderCol...

IMPORTANT: This delegate method is only called in the foreground. Swift func application(application: UIApplication, didReceiveLocalNotification notification: UILocalNotification) { } Objective-C - (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotifi...

The default position of an element is static. To quote MDN: This keyword lets the element use the normal behavior, that is it is laid out in its current position in the flow. The top, right, bottom, left and z-index properties do not apply. .element{ position:static; }

You can define implementation for specific instantiations of a template class/method. For example if you have: template <typename T> T sqrt(T t) { /* Some generic implementation */ } You can then write: template<> int sqrt<int>(int i) { /* Highly optimized integer implement...

Class methods present alternate ways to build instances of classes. To illustrate, let's look at an example. Let's suppose we have a relatively simple Person class: class Person(object): def __init__(self, first_name, last_name, age): self.first_name = first_name self.last...

public class Singleton { private static final Singleton INSTANCE = new Singleton(); private Singleton() {} public static Singleton getInstance() { return INSTANCE; } } It can be argued that this example is effectively lazy initialization. Section 12.4.1 of ...

To increment date objects in Javascript, we can usually do this: var checkoutDate = new Date(); // Thu Jul 21 2016 10:05:13 GMT-0400 (EDT) checkoutDate.setDate( checkoutDate.getDate() + 1 ); console.log(checkoutDate); // Fri Jul 22 2016 10:05:13 GMT-0400 (EDT) It is possible to use setD...

HTML <img src='donald-duck.png' alt='Donald Duck' title='Donald Duck' /> CSS img { -webkit-filter: hue-rotate(120deg); filter: hue-rotate(120deg); } Result

Carousel components can be instantiated via jQuery with the function $('.carousel').carousel(options), where $('.carousel') is a top-level reference to the specific carousel and options is a Javascript object specifying the carousel's default attributes. The options object allows for multiple prope...

using System; using Xamarin.Forms; namespace NavigationApp { public class App : Application { public App() { MainPage = new NavigationPage(new FirstPage()); } } public class FirstPage : ContentPage { Label FirstPage...

Generally you should avoid using the default database role (often postgres) in your application. You should instead create a user with lower levels of privileges. Here we make one called niceusername and give it a password very-strong-password CREATE ROLE niceusername with PASSWORD 'very-strong-pas...

If we want to iterate backwards through a list or vector we can use a reverse_iterator. A reverse iterator is made from a bidirectional, or random access iterator which it keeps as a member which can be accessed through base(). To iterate backwards use rbegin() and rend() as the iterators for the e...

hash( (1, 2) ) # ok hash( ([], {"hello"}) # not ok, since lists and sets are not hashabe Thus a tuple can be put inside a set or as a key in a dict only if each of its elements can. { (1, 2) } # ok { ([], {"hello"}) ) # not ok

Create an instance of UIScrollView with a CGRect as frame. Swift let scrollview = UIScrollView.init(frame: CGRect(x: 0, y: 0, width: 320, height: 400)) Objective-C UIScrollView *scrollview = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 400)];

C# allows user-defined types to control assignment and casting through the use of the explicit and implicit keywords. The signature of the method takes the form: public static <implicit/explicit> operator <ResultingType>(<SourceType> myType) The method cannot take any more argu...

To generate random permutation of 5 numbers: sample(5) # [1] 4 5 3 1 2 To generate random permutation of any vector: sample(10:15) # [1] 11 15 12 10 14 13 One could also use the package pracma randperm(a, k) # Generates one random permutation of k of the elements a, if a is a vector, # ...

Create an individual Localizable.strings file for each language. The right side would be different for each language. Think of it as a key-value pair: "str" = "str-language"; Access str in Objective-C: //Try to provide description on the localized string to be able to create...

Here is an example of a method that would live inside a SQLiteOpenHelper subclass. It uses the searchTerm String to filter the results, iterates through the Cursor's contents, and returns those contents in a List of Product Objects. First, define the Product POJO class that will be the container f...

Arrays You can iterate over nested arrays: [[1, 2], [3, 4]].each { |(a, b)| p "a: #{ a }", "b: #{ b }" } The following syntax is allowed too: [[1, 2], [3, 4]].each { |a, b| "a: #{ a }", "b: #{ b }" } Will produce: "a: 1" "b: 2" ...

Equivalently, we can use the $inject property annotation to achieve the same as above: var MyController = function($scope) { // ... } MyController.$inject = ['$scope']; myModule.controller('MyController', MyController);