Tutorial by Examples: re

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:/...

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 ...

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 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...

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...

The $q constructor function is used to create promises from asynchronous APIs that use callbacks to return results. $q(function(resolve, reject) {...}) The constructor function receives a function that is invoked with two arguments, resolve and reject that are functions which are used to eithe...

If you want to provide a URL out of convenience for your user but map it directly to another one you're already using. Use a redirect: # config/routes.rb TestApp::Application.routes.draw do get 'courses/:course_name' => redirect('/courses/%{course_name}/lessons'), :as => "course&quot...

These Java issues can be very embarrassing, and sometimes remain undiscovered until run in production. Fallthrough behavior in switch statements is often useful; however, missing a “break” keyword when such behavior is not desired can lead to disastrous results. If you have forgotten to put a “break...

Every time a program opens a resource, such as a file or network connection, it is important to free the resource once you are done using it. Similar caution should be taken if any exception were to be thrown during operations on such resources. One could argue that the FileInputStream has a finaliz...

This exception occurs when a collection is modified while iterating over it using methods other than those provided by the iterator object. For example, we have a list of hats and we want to remove all those that have ear flaps: List<IHat> hats = new ArrayList<>(); hats.add(new Ushanka...

ASP.NET Core introduces the concept of dependency injection into Views via the @inject directive via the following syntax : @inject <type> <name> Example Usage Adding this directive into your View will basically generate a property of the given type using the given name within your ...

For Each row As DataRow In FooDataTable.Rows Me.RowsToProcess.Add(row) Next Dim myOptions As ParallelOptions = New ParallelOptions() myOptions.MaxDegreeOfParallelism = environment.processorcount Parallel.ForEach(RowsToProcess, myOptions, Sub(currentRow, state) ...

There are two possible ways to pass a value type by reference: ref and out. The difference is that by passing it with ref the value must be initialized but not when passing it with out. Using out ensures that the variable has a value after the method call: public void ByRef(ref int value) { C...

It is not possible to directly use static_cast, const_cast, dynamic_cast and reinterpret_cast on std::shared_ptr to retrieve a pointer sharing ownership with the pointer being passed as argument. Instead, the functions std::static_pointer_cast, std::const_pointer_cast, std::dynamic_pointer_cast and ...

The tree command lists the contents of a specified directory in a tree-like format. If no directory is specified then, by default, the contents of the current directory are listed. Example Output: $ tree /tmp /tmp ├── 5037 ├── adb.log └── evince-20965    └── image.FPWTJY.png Use the tree ...

Of the LINQ methods which use deferred execution, some require a single value to be evaluated at a time. The following code: var lst = new List<int>() {3, 5, 1, 2}; var streamingQuery = lst.Select(x => { Console.WriteLine(x); return x; }); foreach (var i in streamingQuery) { ...

When a function doesn't preserve units automatically due to lower-level operations, the LanguagePrimitives module can be used to set units on the primitives that support them: /// This cast preserves units, while changing the underlying type let inline castDoubleToSingle (x : float<'u>) : fl...

The [<Measure>] attribute can be used on type parameters to declare types that are generic with respect to units of measure: type CylinderSize<[<Measure>] 'u> = { Radius : float<'u> Height : float<'u> } Test usage: open Microsoft.FSharp.Data.UnitSystems...