Tutorial by Examples: u

Asymmetric encryption has the advantage that a message can be encrypted without exchanging a secret key with the recipient of the message. The sender merely needs to know the recipients public key, this allows encrypting the message in such a way that only the designated recipient (who has the corre...

1. Jenkins : Jenkins is an open source continuous integration tool written in Java. The project was forked from Hudson after a dispute with Oracle. In a nutshell, Jenkins is the leading open source automation server. Built with Java, it provides hundreds of plugins to support building, testing, de...

Setup Spark context in R To start working with Sparks distributed dataframes, you must connect your R program with an existing Spark Cluster. library(SparkR) sc <- sparkR.init() # connection to Spark context sqlContext <- sparkRSQL.init(sc) # connection to SQL context Here are infos how...

If you'd like to quickly test if an ability class is giving the correct permissions, you can initialize an ability in the console or on another context with the rails environment loaded, just pass an user instance to test against: test_ability = Ability.new(User.first) test_ability.can?(:show, Pos...

The QueryClose event is raised whenever a form is about to be closed, whether it's via user action or programmatically. The CloseMode parameter contains a VbQueryClose enum value that indicates how the form was closed: ConstantDescriptionValuevbFormControlMenuForm is closing in response to user act...

$true and $false are two variables that represent logical TRUE and FALSE. Note that you have to specify the dollar sign as the first character (which is different from C#). $boolExpr = "abc".Length -eq 3 # length of "abc" is 3, hence $boolExpr will be True if($boolExpr -eq $tr...

$null is used to represent absent or undefined value. $null can be used as an empty placeholder for empty value in arrays: PS C:\> $array = 1, "string", $null PS C:\> $array.Count 3 When we use the same array as the source for ForEach-Object, it will process all three items (i...

Here are simplified steps (based on the official documentation) required to create a Firebase project and connect it with an Android app. Add Firebase to your app Create a Firebase project in the Firebase console and click Create New Project. Click Add Firebase to your Android app and fol...

From dataframe: mtrdd <- createDataFrame(sqlContext, mtcars) From csv: For csv's, you need to add the csv package to the environment before initiating the Spark context: Sys.setenv('SPARKR_SUBMIT_ARGS'='"--packages" "com.databricks:spark-csv_2.10:1.4.0" "sparkr-shel...

The Phalcon Incubator can be used by the community to experiment with new features or expand onto the existing Phalcon adapters, prototypes or functionalities. Anything in the Incubator can be potentially corporated into the framework. Github repository: https://github.com/phalcon/incubator

Loading the Incubator into your project Add the following lines of code to your loader file $loader = new Phalcon\Loader(); $loader->registerNamespaces([ 'Phalcon' => '/path/to/your/vendor/phalcon/incubator/Library/Phalcon/', // any other namespaces you have loaded // ... ...

This is an example of a simple GET API call wrapped in a promise to take advantage of its asynchronous functionality. var get = function(path) { return new Promise(function(resolve, reject) { let request = new XMLHttpRequest(); request.open('GET', path); request.onload = resolve; ...

Use list() to quick assign a list of variable values into an array. See also compact() // Assigns to $a, $b and $c the values of their respective array elements in $array with keys numbered from zero list($a, $b, $c) = $array; With PHP 7.1 (currently in beta) you will be able to use s...

To create a custom standalone Gradle plug-in using java (you can also use Groovy) you have to create a structure like this: plugin |-- build.gradle |-- settings.gradle |-- src |-- main | |-- java | |-- resources | |-- META-INF | |-- gradle-plugins ...

sys.foreignkeys system view returns information about all foreign key relationships in database: select name, OBJECT_NAME(referenced_object_id) as [parent table], OBJECT_NAME(parent_object_id) as [child table], delete_referential_action_desc, update_referential_action_desc from sys.foreign...

Create a set local set = {} -- empty set Create a set with elements by setting their value to true: local set = {pear=true, plum=true} -- or initialize by adding the value of a variable: local fruit = 'orange' local other_set = {[fruit] = true} -- adds 'orange' Add a member to the ...

Encapsulation hides implementation details from client code. The Handling QueryClose example demonstrates encapsulation: the form has a checkbox control, but its client code doesn't work with it directly - the checkbox is an implementation detail, what the client code needs to know is whether the s...

Swift let bundleIdentifier = NSBundle.mainBundle().bundleIdentifier() NSUserDefaults.standardUserDefaults().removePersistentDomainForName(bundleIdentifier) Objective-C NSString *bundleIdentifier = [[NSBundle mainBundle] bundleIdentifier]; [[NSUserDefaults standardUserDefaults] removePersi...

This example splits cubic and bezier curves in two. The function splitCurveAt splits the curve at position where 0.0 = start, 0.5 = middle, and 1 = end. It can split quadratic and cubic curves. The curve type is determined by the last x argument x4. If not undefined or null then it assumes the curv...

This is a basic Hello World program in NASM assembly for 32-bit x86 Linux, using system calls directly (without any libc function calls). It's a lot to take in, but over time it will become understandable. Lines starting with a semicolon(;) are comments. If you don't already know low-level Unix sy...