Tutorial by Examples: s

The process.env property returns an object containing the user environment. It returns an object like this one : { TERM: 'xterm-256color', SHELL: '/usr/local/bin/bash', USER: 'maciej', PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin', PWD: '/Users/maciej', EDITOR: 'vi...

Spacemacs is a distribution of emacs that comes with a lot of packages preconfigured and easily installed. Also, it is very friendly for those who are familiar with vim style of editing. Spacemacs provides a CIDER-based Clojure layer. To install and configure it for use with Clojure, first install ...

Interfaces should be named with nouns or noun phrases, or adjectives that describe behaviour. For example IComponent uses a descriptive noun, ICustomAttributeProvider uses a noun phrase and IPersistable uses an adjective. Interface names should be prefixed with the letter I, to indicate that the ty...

An iterable is an object that can return an iterator. Any object with state that has an __iter__ method and returns an iterator is an iterable. It may also be an object without state that implements a __getitem__ method. - The method can take indices (starting from zero) and raise an IndexError whe...

As well as allowing module entities to have access control (being public or private) modules entities may also have the protect attribute. A public protected entity may be use associated, but the used entity is subject to restrictions on its use. module mod integer, public, protected :: i=1 en...

Asynchronously var fs = require('fs'); fs.stat('path/to/file', function(err) { if (!err) { console.log('file or directory exists'); } else if (err.code === 'ENOENT') { console.log('file or directory does not exist'); } }); Synchronously here, we must wr...

There may be situations where you have setup a pool of MySQL connections, but you have a number of queries you would like to run in sequence: SELECT 1; SELECT 2; You could just run then using pool.query as seen elsewhere, however if you only have one free connection in the pool you must wait un...

You can attach the query executed to your err object when an error occurs: var q = mysql.query('SELECT `name` FROM `pokedex` WHERE `id` = ?', [ 25 ], function (err, result) { if (err) { // Table 'test.pokedex' doesn't exist err.query = q.sql; // SELECT `name` FROM `pokedex` WHERE `id` ...

This is a collection of unique items, with O(1) lookup. HashSet<int> validStoryPointValues = new HashSet<int>() { 1, 2, 3, 5, 8, 13, 21 }; bool containsEight = validStoryPointValues.Contains(8); // O(1) By way of comparison, doing a Contains on a List yields poorer performance: Lis...

0-1 Knapsack The Knapsack Problem is a problem when given a set of items, each with a weight, a value and exactly 1 copy, determine the which item(s) to include in a collection so that the total weight is less than or equal to a given limit and the total value is as large as possible. C++ Exampl...

Callback-based: db.notification.email.find({subject: 'promisify callback'}, (error, result) => { if (error) { console.log(error); } // normal code here }); This uses bluebird's promisifyAll method to promisify what is conventionally callback-based code like above. blueb...

Dependencies can also be injected by setters. interface Logger { public function log($message); } class Component { private $logger; private $databaseConnection; public function __construct(DatabaseConnection $databaseConnection) { $this->databaseConnection = $...

A view is most useful when it can be used to pull in data from more than one table. CREATE VIEW myview AS SELECT a.*, b.extra_data FROM main_table a LEFT OUTER JOIN other_table b ON a.id = b.id In mysql views are not materialized. If you now perform the simple query SELECT * FROM myview, my...

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The most important application events are: Application_Start - It is raised when the application/website is started. Application_End - It is raised when the application/website is stopped. Similarly, the most used Session events are: Session_Start - It is raised when a user first requests a page...

Common page and control events are: DataBinding - It is raised when a control binds to a data source. Disposed - It is raised when the page or the control is released. Error - It is a page event, occurs when an unhandled exception is thrown. Init - It is raised when the page or the control is in...

The default event for the Page object is Load event. Similarly, every control has a default event. For example, default event for the button control is the Click event. The default event handler could be created in Visual Studio, just by double clicking the control in design view. The following tab...

spray-json provides an easy way to work with JSON. Using implicit formats, everything happens "behind the scenes": Make the Library Available with SBT To manage spray-json with SBT managed library dependencies: libraryDependencies += "io.spray" %% "spray-json" % &quo...

ASP.NET is a unified Web development model that includes the services necessary for you to build enterprise-class Web applications with a minimum of coding. ASP.NET is part of the .NET Framework, and when coding ASP.NET applications you have access to classes in the .NET Framework. You can code you...

Loading the library (ql:quickload "fiveam") Define a test case (fiveam:test sum-1 (fiveam:is (= 3 (+ 1 2)))) ;; We'll also add a failing test case (fiveam:test sum2 (fiveam:is (= 4 (+ 1 2)))) Run tests (fiveam:run!) which reports Running test suite NIL Running test...