Tutorial by Examples: en

async.series(tasks, afterTasksCallback) will execute a set of tasks. Each task are executed after another. If a task fails, async stops immediately the execution and jump into the main callback. When tasks are finished successfully, async call the "master" callback with all errors and all...

async.waterfall(tasks, afterTasksCallback) will execute a set of tasks. Each task are executed after another, and the result of a task is passed to the next task. As async.series(), if a task fails, async stop the execution and call immediately the main callback. When tasks are finished successfull...

SELECT name, caption as title, year, pages FROM books UNION SELECT name, title, year, 0 as pages FROM movies When combining 2 record sets with different columns then emulate the missing ones with default values.

extern int var; static int var; /* Undefined behaviour */ C11, §6.2.2, 7 says: If, within a translation unit, the same identifier appears with both internal and external linkage, the behavior is undefined. Note that if an prior declaration of an identifier is visible then it'll have the pri...

Use the yum command to manage packages in Enterprise Linux-based operating systems: yum install php This installs a minimal install of PHP including some common features. If you need additional modules, you will need to install them separately. Once again, you can use yum to search for these pac...

Note: There will be some Objective-c in this example.. We will make a wrapper to C++ in this example, So don't worry to much about it. First start Xcode and create a project. And select a Cocoa application Delete all sources except the Info.plist file.(Your app won't work without it) Creat...

C# developers get a lot of null reference exceptions to deal with. F# developers don't because they have the Option type. An Option<> type (some prefer Maybe<> as a name) provides a Some and a None return type. It makes it explicit that a method may be about to return a null record. For...

The assignment operator = sets thr left hand operand's value to the value of right hand operand, and return that value: int a = 3; // assigns value 3 to variable a int b = a = 5; // first assigns value 5 to variable a, then does the same for variable b Console.WriteLine(a = 3 + 4); // prints ...

enum Util { /* No instances */; public static int clamp(int min, int max, int i) { return Math.min(Math.max(i, min), max); } // other utility methods... } Just as enum can be used for singletons (1 instance classes), it can be used for utility classes (0 instance...

The http_build_query() will create a query string from an array or object. These strings can be appended to a URL to create a GET request, or used in a POST request with, for example, cURL. $parameters = array( 'parameter1' => 'foo', 'parameter2' => 'bar', ); $queryString = http_b...

Basic usage If the value of the href-attribute begins with mailto: it will try to open an email client on click: <a href="mailto:[email protected]">Send email</a> This will put the email address [email protected] as the recipient for the newly created email. Cc and ...

When INSERTing, you can use OUTPUT INSERTED.ColumnName to get values from the newly inserted row, for example the newly generated Id - useful if you have an IDENTITY column or any sort of default or calculated value. When programatically calling this (e.g., from ADO.net) you would treat it as a nor...

It is sometimes argued that, for the sake of efficiency, we must accept the use of non-monotonic constructs in real-world Prolog programs. There is no evidence for this. Recent research indicates that the pure monotonic subset of Prolog may not only be sufficient to express most real-world programs...

To interact with WebElements in a webpage, first we need to identify the location of the element. By is the keyword available in selenium. You can locate the elements By.. By ID By Class Name By TagName By Name By Link Text By Partial Link Text By CSS Selector By XPath Using JavaScript ...

set can also be invoked with just one argument. When called with just one argument, it returns the contents of that argument. % set x 235 235 % set x 235

Unlike emails, JIDs were defined with Internationalization (i18n) in mind using the Preparation, Enforcement, and Comparison of Internationalized Strings (PRECIS) framework. PRECIS (defined in RFC 7564), is a framework for comparing strings safely in a variety of contexts. For instance, imagine you...

Adding a footer is not natively possible. Luckily, we can make use of jQuery and CSS to add a footer to the slides of an ioslides presentation rendered with knitr. First of all we have to include the jQuery plugin. This is done by the line <script src="https://ajax.googleapis.com/ajax/libs...

Below code is simple java program using selenium. The journey of the below code is Open Firefox browser Open google page Print title of Google page Find the search box location Pass the value as Selenium in the search box Submit the form Shutdown the browser package org.openqa.selenium....

The first interesting thing to know is how to write comments. In VB .NET, you write a comment by writing an apostrophe ' or writing REM. This means the rest of the line will not be taken into account by the compiler. 'This entire line is a comment Dim x As Integer = 0 'This comment is here to say...

One interesting thing is the ability to add you own comments into Visual Studio Intellisense. So you can make your own written functions and classes self-explanatory. To do so, you must type the comment symbol three times the line above your function. Once done, Visual Studio will automatically add...