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The core concepts of RxJava are its Observables and Subscribers. An Observable emits objects, while a Subscriber consumes them. Observable Observable is a class that implements the reactive design pattern. These Observables provide methods that allow consumers to subscribe to event changes. The ev...

Swift let alert = UIAlertController(title: "Hello", message: "Welcome to the world of iOS", preferredStyle: UIAlertControllerStyle.alert) let defaultAction = UIAlertAction(title: "OK", style: UIAlertActionS...

To spawn a new process in which you need unbuffered output (e.g. long-running processes which might print output over a period of time rather than printing and exiting immediately), use child_process.spawn(). This method spawns a new process using a given command and an array of arguments. The retu...

This command will drop index in the table. It works on SAP ASE server. Syntax: DROP INDEX [table name].[index name] Example: DROP INDEX Cars.index_1

Prerequisites Installation

If value types are assigned to variables of type object they are boxed - the value is stored in an instance of a System.Object. This can lead to unintended consequences when comparing values with ==, e.g.: object left = (int)1; // int in an object box object right = (int)1; // int in an object bo...

Boxed value types can only be unboxed into their original Type, even if a conversion of the two Types is valid, e.g.: object boxedInt = (int)1; // int boxed in an object long unboxedInt1 = (long)boxedInt; // invalid cast This can be avoided by first unboxing into the original Type, e.g.: lon...

Use the speakUtterance: method of AVSpeechSynthesizer to convert text to speech. You need to pass an AVSpeechUtterance object to this method, which contains the text that you want to be spoken. Objective C AVSpeechSynthesizer *speaker = [[AVSpeechSynthesizer alloc] init]; AVSpeechUtterance *speec...

public static void Main() { var xml = new XmlDocument(); var root = xml.CreateElement("element"); // Creates an attribute, so the element will now be "<element attribute='value' />" root.SetAttribute("attribute", "value"); ...

This is a very common Exception. It causes your application to stop during the start or execution of your app. In the LogCat you see the message: android.content.ActivityNotFoundException : Unable to find explicit activity class; have you declared this activity in your AndroidManifest.xml? In ...

HTML <p>My shadow always follows me.</p> CSS p { -webkit-filter: drop-shadow(10px 10px 1px green); filter: drop-shadow(10px 10px 1px green); } Result

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...

A Simple FXML document outlining an AnchorPane containing a button and a label node: <?xml version="1.0" encoding="UTF-8"?> <?import java.lang.*?> <?import java.util.*?> <?import javafx.scene.*?> <?import javafx.scene.control.*?> <?import ...

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" ...

Extension methods are useful to extend the behaviour of libraries we don't own. They are used similar to instance methods thanks to the compiler's syntactic sugar: Sub Main() Dim stringBuilder = new StringBuilder() 'Extension called directly on the object. stringBuilder.AppendIf(t...

A good use of extension method is to make the language more functional Sub Main() Dim strings = { "One", "Two", "Three" } strings.Join(Environment.NewLine).Print() End Sub <Extension> Public Function Join(strings As IEnumerable(Of String), separa...

A namespace is a URI, but to avoid verbosity, prefixes are used as a proxy. In the following example, the prefix my-prefix is bound to the namespace http://www.example.com/my-namespace by using the special attribute xmlns:my-prefix (my-prefix can be replaced with any other prefix): <?xml versio...

These two documents are semantically equivalement, as namespaces matter, not prefixes. <?xml version="1.0"?> <myns:foo xmlns:myns="http://www.example.com/my-namespace"> </myns:foo> <?xml version="1.0"?> <ns:foo xmlns:ns="http://www...

First, add relevant dependencies into the build.gradle file. dependencies { .... compile 'com.squareup.retrofit2:retrofit:2.3.0' compile 'com.squareup.retrofit2:converter-gson:2.3.0' compile 'com.squareup.retrofit2:adapter-rxjava:2.3.0' .... } Then create the model you ...

Use Ctrl + C, Ctrl + C to exit iex(1)> BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded (v)ersion (k)ill (D)b-tables (d)istribution Use Ctrl+ \ to immediately exit