Tutorial by Examples: r

// 1. Instantiate an AlertDialog.Builder with its constructor // the parameter this is the context (usually your activity) AlertDialog.Builder builder = new AlertDialog.Builder(this); // 2. Chain together various setter methods to set the dialog characteristics builder.SetMessage(Resource.Str...

Cursors enable you to itterate results of query one by line. DECLARE command is used to init cursor and associate it with a specific SQL query: DECLARE student CURSOR FOR SELECT name FROM studend; Let's say we sell products of some types. We want to count how many products of each type are exis...

In performing parsing, before starting, the grammar for the language needs to be specified. A source of tokens is also needed for the parser. The parser could be hand-written code, or a parser generator tool could be used. If a parser generator tool is used, then that tool will need to be downloade...

WPF introduces a very handy concept: The ability to store data as a resource, either locally for a control, locally for the entire window or globally for the entire application. The data can be pretty much whatever you want, from actual information to a hierarchy of WPF controls. This allows you to ...

Sharing a simple string was easy, but you can do much more. In this example, I'll also store a complete array of strings, along with a gradient brush to be used for the background. This should give you a pretty good idea of just how much you can do with resources: <Window x:Class="WPFApplic...

If you only need a given resource for a specific control, you can make it more local by adding it to this specific control, instead of the window. It works exactly the same way, the only difference being that you can now only access from inside the scope of the control where you put it: <StackPa...

In this example, we'll be accessing three different resources from Code-behind, each stored in a different scope App.xaml: <Application x:Class="WpfSamples.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http:/...

Polymorphism is one of the pillar of OOP. Poly derives from a Greek term which means 'multiple forms'. Below is an example which exhibits Polymorphism. The class Vehicle takes multiple forms as a base class. The Derived classes Ducati and Lamborghini inherits from Vehicle and overrides the base cl...

in this way '0' representing the known values ​​are ranked first, '1' representing the NULL values ​​are sorted by the last: SELECT ID ,REGION ,CITY ,DEPARTMENT ,EMPLOYEES_NUMBER FROM DEPT ORDER BY CASE WHEN REGION IS NULL THEN 1 ELSE 0 END, REGION ...

If you need to send events from fragment to activity, one of the possible solutions is to define callback interface and require that the host activity implement it. Example Send callback to an activity, when fragment's button clicked First of all, define callback interface: public interface Samp...

This is an example for how to handle dynamic key for response. Here A and B are dynamic keys it can be anything Response { "response": [ { "A": [ { "name": "Tango" }, { "name": "P...

CREATE TABLE ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, ... PRIMARY KEY(id), ... ); Main notes: Starts with 1 and increments by 1 automatically when you fail to specify it on INSERT, or specify it as NULL. The ids are always distinct from each other, but... Do not make a...

The ToString method on an enum returns the string name of the enumeration. For instance: Module Module1 Enum Size Small Medium Large End Enum Sub Main() Dim shirtSize As Size = Size.Medium Dim output As String = shirtSize.ToString() ...

The following examples use the UTF-8 encoding to represent filenames (and directory names) on disk. If you want to use another encoding, you should use Encode::encode(...). use v5.14; # Make Perl recognize UTF-8 encoded characters in literal strings. # For this to work: Make sure your text-editor...

Perl does not attempt to decode filenames returned by builtin functions or modules. Such strings representing filenames should always be decoded explicitly, in order for Perl to recognize them as Unicode. use v5.14; use Encode qw(decode_utf8); # Ensure that possible error messages printed to sc...

Some common operations in MATLAB, like differentiation or integration, output results that have a different amount of elements than the input data has. This fact can easily be overlooked, which would usually cause errors like Matrix dimensions must agree. Consider the following example: t = 0:0.1:1...

Recursive type Discriminated unions can be recursive, that is they can refer to themselves in their definition. The prime example here is a tree: type Tree = | Branch of int * Tree list | Leaf of int As an example, let's define the following tree: 1 2 5 3 4 We can defi...

Polymorphism means that a operation can also be applied to values of some other types. There are multiple types of Polymorphism: Ad hoc polymorphism: contains function overloading. The target is that a Method can be used with different types without the need of being generic. Parametric polym...

You can use parfor to execute the iterations of a loop in parallel: Example: poolobj = parpool(2); % Open a parallel pool with 2 workers s = 0; % Performing some parallel Computations parfor i=0:9 s = s + 1; end disp(s) % Outputs '10' d...

You can use the $q.all function to call a .then method after an array of promises has been successfully resolved and fetch the data they resolved with. Example: JS: $scope.data = [] $q.all([ $http.get("data.json"), $http.get("more-data.json"), ]).then(funct...