Tutorial by Examples: r

Absolute value: $ for n in -8 -2 0 3 4; do > echo $((n<0?-n:n)) > done 8 2 0 3 4 Fix variable range: $ min=2 $ max=4 $ for n in 1 2 3 4 5; do > echo $((n<min?min:n>max?max:n)) > done 2 2 3 4 4

$ ispow2() { return $((!($1!=0&&($1&$1-1)==0))); } $ i=0 $ while [ $i -lt 100 ]; do > if ispow2 $((i=i+1)); then > echo $i > fi > done 1 2 4 8 16 32 64 $1!=0 0 is not a power of 2. ($1&$1-1)==0 Unset the lowest bit. If it was the only bit...

Open routes file. Paste the following code in: Route::get('helloworld', function () { return '<h1>Hello World</h1>'; }); after going to route localhost/helloworld it displays Hello World. The routes file is located: 5.3 For Web routes/web.php For APIs routes/api.php ...

Remove the token from the client storage to avoid usage Tokens are issued by the server and you can not force browsers to delete a cookie/localStorage or control how external clients are managing your tokens. Obviously if attackers have stolen the token before logout they still could use the token,...

Set expiration time short and rotate tokens. Issue a new access token every few request. Use refresh tokens to allow your application to obtain new access tokens without needing to re-authenticate Refresh and access tokens access token: Authorize access to a protected resource. Limited lifetim...

Allow change user unique ID if account is compromised with a new user&password login To invalidate tokens when user changes their password or permissions, sign the token with a hash of those fields. If any of these field change, any previous tokens automatically fail to verify. The down...

This is a simple example to search in Google. It containt two parts, Feature File Step Definition File Am not going into much details here as the code itself is self explanatory. Feature File Feature:Google Key word search @mytag Scenario: search Spec Flow in Google search bar Given...

This will download libpng from the official "git" repository and build it in your "libpng" directory. git clone https://github.com/glennrp/libpng.git libpng cd libpng ./autogen.sh ./configure [--prefix=/path] make install where "/path" points to the installation...

Basic architecture examples on how development for embedded systems works (i.e. IDEs, cross-compiling, downloading, in-line debugging, JTAG,...) and what would be the minimum requirements for starting. It would be worth mentioning different approaches and platforms from begginers-higher level to ad...

import { expect } from 'chai'; import { createStore } from 'redux'; describe('redux store test demonstration', () => { describe('testReducer', () => { it('should increment value on TEST_ACTION', () => { // define a test reducer with initial state: test: 0 const te...

HtmlHelper.Action() @Html.Action(actionName: "Index") output: The HTML rendered by an action method called Index() @Html.Action(actionName: "Index", routeValues: new {id = 1}) output: The HTML rendered by an action method called Index(int id) @(Html.Action("In...

Project structure project/ group_vars/ development inventory.development playbook.yaml These variables will be applied to hosts under the development group due to the filename. --- ## Application app_name: app app_url: app.io web_url: cdn.io app_friendly: New App env_type: ...

A very simple example would be to fade out an SKSpriteNode. In Swift: let node = SKSpriteNode(imageNamed: "image") let action = SKAction.fadeOutWithDuration(1.0) node.runAction(action)

Sometimes it is necessary to do an action on repeat or in a sequence. This example will make the node fade in and out a total of 3 times. In Swift: let node = SKSpriteNode(imageNamed: "image") let actionFadeOut = SKAction.fadeOutWithDuration(1.0) let actionFadeIn = SKAction.fadeInWithD...

One helpful case is to have the action run a block of code. In Swift: let node = SKSpriteNode(imageNamed: "image") let actionBlock = SKAction.runBlock({ //Do what you want here if let gameScene = node.scene as? GameScene { gameScene.score += 5 } }) node.runActi...

If you want to use docker for rails app, and use database, you need to know that all the data in the docker container will be destroyed (unless you configure the container specifically for keeping data) Sometimes, you need to create a docker container with an application and attach it to an old con...

To select an element by an exact HTML attribute use the css locator pattern [attribute=value] //selects the first element with href value '/contact' element(by.css('[href="/contact"]')); //selects the first element with tag option and value 'foo' element(by.css('option[value="f...

To select an element by an HTML attribute that contains a specified value use the css locator pattern [attribute*=value] //selects the first element with href value that contains'cont' element(by.css('[href*="cont"]')); //selects the first element with tag h1 and class attribute that...

Sometimes users from other regions than English-speaking have problems with encoding while for example programming a php project. It can be, that the server has another encoding then UTF-8, and if someone want to create a php project in UTF-8 on this server, his text might be shown incorrect. Examp...

One of most common use cases of Gitflow Initialize repo and define branches $ git flow init # if you use default setup, you'll define six types of branches: # # main branches (lives forever) # # 1. master: for production releases # 2. develop: for "next ...