Tutorial by Examples: r

The complete sample code for this application (Android + Node server) is available in the PayPal Developer Github repository. From step 2, an async request has been made to our server at the /fpstore endpoint, passing along the auth code and metadata ID. We now need to exchange those for a token in...

XSD schema (schema.xsd) The following xml schema (xsd) defines a list of users with attributes name and reputation. <?xml version="1.0"?> <xs:schema version="1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ns="http://www...

Review Partial Application before proceeding. In Haskell, a function that can take other functions as arguments or return functions is called a higher-order function. The following are all higher-order functions: map :: (a -> b) -> [a] -> [b] filter :: (a -> Bool) -> [a] ...

Lets say we have a class Classy that has property Propertua public class Classy { public string Propertua {get; set;} } to set Propertua using reflection: var typeOfClassy = typeof (Classy); var classy = new Classy(); var prop = typeOfClassy.GetProperty("Propertua"); prop.Se...

When editing text, a common task is to navigate to a particular word on the screen. In these examples we explore how we can navigate to the word updated. For the sake of consistency across the examples, we aim to land on the first letter of the word. Mid-screen jump M$B This approach is quick...

Every tag has an overview topic. This topic has a special section named "Versions". In that section, different versions can be defined in a table that has that should have at least 2 columns: the first one should be the name of the version the last one should be the release ...

For some tags it makes sense to have multiple version tables. There might be different subsets of a programming language or framework available, say for different device types as in this example. The different tables should be prefaced with a heading. This markup: ## desktop development kit ## ...

A topic might only apply to certain versions. When creating a new topic, the appropriate versions can be chosen in the title section of the topic. In the following example .NET 2.0, 4.0, 4.5.1; Compact Framework 3.7 and Micro Framework 4.2 are selected. This selection will show up next to the to...

An example cannot be associated with a version number directly. Parts of it can however be declared to apply only for certain versions. <!-- if version [eq Java SE 1.3] --> This content is for Java SE 1.3 <!-- end version if -->

If there are many version tables, the title of the desired one has to be included in angle brackets. <!-- if version <Micro Framework> [eq 4.4] --> This content is for Micro Framework 4.4 <!-- end version if -->

The command :g/apples/y A will yank all lines containing the word apples into the a register, which can be pasted with "ap. Any regular expression can be used. Note the space before the A, and the capitalization of the register letter. If a capital letter is used as the yank register, matc...

Returns character data (varchar) converted from numeric data. Parameters: float expression. An approximate numeric data type with a decimal point. length. optional. The total length of the string expression that would return, including digits, decimal point and leading spaces (if needed). The d...

@parallel can be used to parallellize a loop, dividing steps of the loop up over different workers. As a very simple example: addprocs(3) a = collect(1:10) for idx = 1:10 println(a[idx]) end For a slightly more complex example, consider: @time begin @sync begin @paral...

The Julia documentation advises that pmap() is designed for the case where each function call does a large amount of work. In contrast, @parallel for can handle situations where each iteration is tiny, perhaps merely summing two numbers. There are several reasons for this. First, pmap incurs ...

When you first start Julia, by default, there will only be a single process running and available to give work to. You can verify this using: julia> nprocs() 1 In order to take advantage of parallel processing, you must first add additional workers who will then be available to do work that...

SELECT @@VERSION Returns the version of MS SQL Server running on the instance. SELECT @@SERVERNAME Returns the name of the MS SQL Server instance. SELECT @@SERVICENAME Returns the name of the Windows service MS SQL Server is running as. SELECT serverproperty('ComputerNamePhysicalNetBIOS'...

Whenever you change data, in a Data Manipulation Language(DML) command, you can wrap your changes in a transaction. DML includes UPDATE, TRUNCATE, INSERT and DELETE. One of the ways that you can make sure that you're changing the right data would be to use a transaction. DML changes will take a loc...

To create a view with an index, the view must be created using the WITH SCHEMABINDING keywords: CREATE VIEW view_EmployeeInfo WITH SCHEMABINDING AS SELECT EmployeeID, FirstName, LastName, HireDate FROM [dbo].Employee GO Any clustered or non-clustered ...

Stored procedures can return values using the OUTPUT keyword in its parameter list. Creating a stored procedure with a single out parameter CREATE PROCEDURE SprocWithOutParams ( @InParam VARCHAR(30), @OutParam VARCHAR(30) OUTPUT ) AS BEGIN SELECT @OutParam = @InParam + ' must co...

One might want to GROUP BY more than one column declare @temp table(age int, name varchar(15)) insert into @temp select 18, 'matt' union all select 21, 'matt' union all select 21, 'matt' union all select 18, 'luke' union all select 18, 'luke' union all select 21, 'luke' union all select 1...