Tutorial by Examples: di

A simple cursor syntax, operating on a few example test rows: /* Prepare test data */ DECLARE @test_table TABLE ( Id INT, Val VARCHAR(100) ); INSERT INTO @test_table(Id, Val) VALUES (1, 'Foo'), (2, 'Bar'), (3, 'Baz'); /* Test data prepared */ /* Iterator variabl...

By default, the caret ^ metacharacter matches the position before the first character in the string. Given the string "charsequence" applied against the following patterns: /^char/ & /^sequence/, the engine will try to match as follows: /^char/ ^ - charsequence c - charsequ...

The Python interpreter compiles code to bytecode before executing it on the Python's virtual machine (see also What is python bytecode?. Here's how to view the bytecode of a Python function import dis def fib(n): if n <= 2: return 1 return fib(n-1) + fib(n-2) # Display the disas...

Dictionaries map keys to values. car = {} car["wheels"] = 4 car["color"] = "Red" car["model"] = "Corvette" Dictionary values can be accessed by their keys. print "Little " + car["color"] + " " + car["model&q...

Given this setup code: var dict = new Dictionary<int, string>() { { 1, "First" }, { 2, "Second" }, { 3, "Third" } }; Use the Remove method to remove a key and its associated value. bool wasRemoved = dict.Remove(2); Executing this code remo...

In Julia, a for loop can contain a comma (,) to specify iterating over multiple dimensions. This acts similarly to nesting a loop within another, but can be more compact. For instance, the below function generates elements of the Cartesian product of two iterables: function cartesian(xs, ys) f...

pushunique!(A, x) = x in A ? A : push!(A, x) The ternary conditional operator is a less wordy if...else expression. The syntax specifically is: [condition] ? [execute if true] : [execute if false] In this example, we add x to the collection A only if x is not already in A. Otherwise, we jus...

// 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...

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...

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...

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...

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 ...

The basic math operations are performed mainly on numbers or on vectors (lists of numbers). 1. Using single numbers We can simple enter the numbers concatenated with + for adding and - for subtracting: > 3 + 4.5 # [1] 7.5 > 3 + 4.5 + 2 # [1] 9.5 > 3 + 4.5 + 2 - 3.8 # [1] 5.7 >...

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...

ChoiceDialog allows the user to pick one item from a list of options. List<String> options = new ArrayList<>(); options.add("42"); options.add("9"); options.add("467829"); options.add("Other"); ChoiceDialog<String> dialog = new Choice...

For example, types for SI units have been standardized in the F# core library, in Microsoft.FSharp.Data.UnitSystems.SI. Open the appropriate sub-namespace, UnitNames or UnitSymbols, to use them. Or, if only a few SI units are required, they can be imported with type aliases: /// Seconds, the SI uni...

After Successfully installing Xamarin Studio on OS X. It's time for the first Hello World Application. Hello World Application: Xamarin.Forms What is Xamarin Forms : Xamarin.Forms is a new library that enables you to build native UIs for iOS, Android and Windows Phone from a single, shared C# c...

This example shows how to establish a connection to an SSL-enabled POP3 email server and send a simple (text only) email. // Configure mail provider Properties props = new Properties(); props.put("mail.smtp.host", "smtp.mymailprovider.com"); props.put("ma...

A dictionary object has the method copy. It performs a shallow copy of the dictionary. >>> d1 = {1:[]} >>> d2 = d1.copy() >>> d1 is d2 False >>> d1[1] is d2[1] True