Tutorial by Examples: s

tl;dr : Create a base class that defines two user objects (say user and another_user). Create your other models and define three Client instances. self.client : Representing user logged in browser self.another_client : Representing another_user 's client self.unlogged_client : Representing unlo...

Filters are a special type of function that can modify how something is printed out to the page, or can be used to filter an array, or a ng-repeat action. You can create a filter by calling the app.filter() method, passing it a name and a function. See the examples below for details on syntax. Fo...

package main import ( "log" "text/template" "os" ) type Person struct{ MyName string MyAge int } var myTempContents string= ` This person's name is : {{.MyName}} And he is {{.MyAge}} years old. ` func main() { t,err := temp...

To assign variables from the command-line, -v can be used: $ awk -v myvar="hello" 'BEGIN {print myvar}' hello Note that there are no spaces around the equal sign. This allows to use shell variables: $ shell_var="hello" $ awk -v myvar="$shell_var" 'BEGIN {print m...

You can nest quotes simply by including multiple > characters, like so: > Often makes no sense. > > Commenting above your quote… Often makes no sense. Commenting above your quote…

Node Version Manager, otherwise known as nvm, is a bash script that simplifies the management of multiple Node.js versions. To install nvm, use the provided install script: $ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.3/install.sh | bash For windows there is a nvm-windows p...

Rcpp Attributes makes the process of working with R and C++ straightforward. The form of attributes take: // [[Rcpp::attribute]] The use of attributes is typically associated with: // [[Rcpp::export]] that is placed directly above a declared function header when reading in a C++ file via sou...

Within C++, one can set different compilation flags using: // [[Rcpp::plugins(name)]] List of the built-in plugins: // built-in C++11 plugin // [[Rcpp::plugins(cpp11)]] // built-in C++11 plugin for older g++ compiler // [[Rcpp::plugins(cpp0x)]] // built-in C++14 plugin for C++14 standa...

In some cases you may want to wrap a synchronous operation inside a promise to prevent repetition in code branches. Take this example: if (result) { // if we already have a result processResult(result); // process it } else { fetchResult().then(processResult); } The synchronous and async...

Cloning a huge repository (like a project with multiple years of history) might take a long time, or fail because of the amount of data to be transferred. In cases where you don't need to have the full history available, you can do a shallow clone: git clone [repo_url] --depth 1 The above comman...

When you want to use user generated content in the SQL, it with done with parameters. For example for searching user with the name aminadav you should do: var username = 'aminadav'; var querystring = 'SELECT name, email from users where name = ?'; connection.query(querystring, [username], functi...

a. Running multiple queries at same time All queries in MySQL connection are done one after another. It means that if you want to do 10 queries and each query takes 2 seconds then it will take 20 seconds to complete whole execution. The solution is to create 10 connection and run each query in a di...

One of the easiest ways to connect to MySQL is by using mysql module. This module handles the connection between Node.js app and MySQL server. You can install it like any other module: npm install --save mysql Now you have to create a mysql connection, which you can later query. const mysql ...

You send the query as a string and in response callback with the answer is received. The callback gives you error, array of rows and fields. Each row contains all the column of the returned table. Here is a snippet for the following explanation. connection.query('SELECT name,email from users', fu...

Follow previous example of creating a seed. This example uses a MySQL Dump to seed a table in the project database. The table must be created before seeding. <?php use Illuminate\Database\Seeder; class UserTableSeeder extends Seeder { /** * Run the database seeds. * ...

You may define scripts in your package.json, for example: { "name": "your-package", "version": "1.0.0", "description": "", "main": "index.js", "author": "", "license": &qu...

You can use a RecyclerView.ItemDecoration to put extra margins around each item in a RecyclerView. This can in some cases clean up both your adapter implementation and your item view XML. public class MyItemDecoration extends RecyclerView.ItemDecoration { private final int extraMargin; ...

You can group multiple boolean logic statements within parenthesis in order to create a more complex logic evaluation, especially useful in if statements. if ((age >= 18 && height >= 5.11) || (status === 'royalty' && hasInvitation)) { console.log('You can enter our club'); ...

__call() and __callStatic() are called when somebody is calling nonexistent object method in object or static context. class Foo { /** * This method will be called when somebody will try to invoke a method in object * context, which does not exist, like: * * $foo->...

__sleep and __wakeup are methods that are related to the serialization process. serialize function checks if a class has a __sleep method. If so, it will be executed before any serialization. __sleep is supposed to return an array of the names of all variables of an object that should be serializ...