Tutorial by Examples: p

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...

strip_tags is a very powerful function if you know how to use it. As a method to prevent cross-site scripting attacks there are better methods, such as character encoding, but stripping tags is useful in some cases. Basic Example $string = '<b>Hello,<> please remove the <> tags.&...

The GNU gprof profiler, gprof, allows you to profile your code. To use it, you need to perform the following steps: Build the application with settings for generating profiling information Generate profiling information by running the built application View the generated profiling inf...

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...

SQL Server 2012 In Transact SQL , you may define an object as Date (or DateTime) using the [DATEFROMPARTS][1] (or [DATETIMEFROMPARTS][1]) function like following: DECLARE @myDate DATE=DATEFROMPARTS(1988,11,28) DECLARE @someMoment DATETIME=DATEFROMPARTS(1988,11,28,10,30,50,123) The parameter...

A UserForm is a class module with a designer and a default instance. The designer can be accessed by pressing Shift+F7 while viewing the code-behind, and the code-behind can be accessed by pressing F7 while viewing the designer. Work with a new instance every time. Being a class module, a form i...

import groovy.json.JsonSlurper; def jsonSlurper = new JsonSlurper() def obj = jsonSlurper.parseText('{ "foo": "bar", "baz": [1] }') assert obj.foo == 'bar' assert obj.baz == [1]

import groovy.json.JsonSlurper; def jsonSlurper = new JsonSlurper() File fl = new File('/path/to/fils.json') // parse(File file) method is available since 2.2.0 def obj = jsonSlurper.parse(fl) // for versions < 2.2.0 it's possible to use def old = jsonSlurper.parse(fl.text)

import groovy.json.JsonOutput; def json = JsonOutput.toJson([foo: 'bar', baz: [1]]) assert json == '{"foo":"bar","baz":[1]}' def pretty = JsonOutput.prettyPrint(json) assert pretty == '''{ "foo": "bar", "baz": [ ...

Contains process ID of the current hosting process. PS C:\> $pid 26080

Contains the object/item currently being processed by the pipeline. PS C:\> 1..5 | % { Write-Host "The current item is $_" } The current item is 1 The current item is 2 The current item is 3 The current item is 4 The current item is 5 $PSItem and $_ are identical and can be use...

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...

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; ...

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 ...

set var=10 set /a var=%var%+10 echo %var% The final value of var is 20. The second line is not working within a command block used for example on an IF condition or on a FOR loop as delayed expansion would be needed instead of standard environment variable expansion. Here is another, better w...

Foreign keys enables you to define relationship between two tables. One (parent) table need to have primary key that uniquely identifies rows in the table. Other (child) table can have value of the primary key from the parent in one of the columns. FOREIGN KEY REFERENCES constraint ensures that valu...

Let's assume that we have one row in Company table with companyId 1. We can insert row in employee table that has companyId 1: insert into Employee values (17, 'John', 1) However, we cannot insert employee that has non-existing CompanyId: insert into Employee values (17, 'John', 111111) Msg ...

FOREIGN KEY constraint can be added on existing tables that are still not in relationship. Imagine that we have Company and Employee tables where Employee table CompanyId column but don't have foreign key relationship. ALTER TABLE statement enables you to add foreign key constraint on an existing c...

Bitwise shifting can be thought as "moving" the bits either left or right, and hence changing the value of the data operated on. Left Shift The left shift operator (value) << (shift amount) will shift the bits to the left by (shift amount) bits; the new bits coming in from the righ...