Tutorial by Examples: r

Data classes in kotlin are classes created to do nothing but hold data. Such classes are marked as data: data class User(var firstname: String, var lastname: String, var age: Int) The code above creates a User class with the following automatically generated: Getters and Setters for all prope...

val list = listOf(1,2,3,4,5,6) //filter out even numbers val even = list.filter { it % 2 == 0 } println(even) //returns [2,4]

The two main libraries providing pattern matching in Common Lisp are Optima and Trivia. Both provide a similar matching API and syntax. However trivia provides a unified interface to extend matching, defpattern.

Because a clack request is represented as a plist, we can use pattern matching as the entry point to the clack app as a way to route request to their appropriate controllers (defvar *app* (lambda (env) (match env ((plist :request-method :get :request-uri uri) (...

Rails is shipped by default with ActiveRecord, an ORM (Object Relational Mapping) derived from the pattern with the same name. As an ORM, it is built to handle relational-mapping, and more precisely by handling SQL requests for you, hence the limitation to SQL databases only. However, you can stil...

This is a sample adapter code. public class SampleAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { private static final int FOOTER_VIEW = 1; // Define a view holder for Footer view public class FooterViewHolder extends ViewHolder { public FooterViewHolder(View ite...

If your project doesn't have README.md, GitHub may parse README.rdoc to display details. If it has both, it will use README.md, silently ignoring rdoc. A README file may include- Project Title Describe briefly about your project. You may also provide project's website link, badges, community ...

Fish shell is friendlier yet you might face trouble while using with virtualenv or virtualenvwrapper. Alternatively virtualfish exists for the rescue. Just follow the below sequence to start using Fish shell with virtualenv. Install virtualfish to the global space sudo pip install virtualfish...

Content has been moved back to good 'ol Servlets wiki page

Content has been moved back to good 'ol Servlets wiki page

Content has been moved back to good 'ol Servlets wiki page

Strategy: Strategy is a behavioural pattern, which allows to change the algorithm dynamically from a family of related algorithms. UML of Strategy pattern from Wikipedia : import java.util.*; /* Interface for Strategy */ interface OfferStrategy { public String getName(); public dou...

from scipy.sparse import csr_matrix A = csr_matrix([[1,0,2],[0,3,0]]) >>>A <2x3 sparse matrix of type '<type 'numpy.int64'>' with 3 stored elements in Compressed Sparse Row format> >>> A.todense() matrix([[1, 0, 2], [0, 3, 0]]) >>&g...

An Explain infront of a select query shows you how the query will be executed. This way you to see if the query uses an index or if you could optimize your query by adding an index. Example query: explain select * from user join data on user.test = data.fk_user; Example result: id select_type...

The type alias keyword combination gives a new name for a type, but the type keyword in isolation declares a new type. Let's examine one of the most fundamental of these types: Maybe type Maybe a = Just a | Nothing The first thing to note is that the Maybe type is declared with a type ...

There are several sort functions for arrays in php: sort() Sort an array in ascending order by value. $fruits = ['Zitrone', 'Orange', 'Banane', 'Apfel']; sort($fruits); print_r($fruits); results in Array ( [0] => Apfel [1] => Banane [2] => Orange [3] => Zitr...

Fired when the component or directive instance is destroyed. import { Component, OnDestroy } from '@angular/core'; @Component({ selector: 'so-ondestroy-component', templateUrl: 'ondestroy-component.html', styleUrls: ['ondestroy-component.'] }) class OnDestroyComponent implements...

Fire after the initialization of the content of the component or directive has finished. (Right after OnInit) import { Component, AfterContentInit } from '@angular/core'; @Component({ selector: 'so-aftercontentinit-component', templateUrl: 'aftercontentinit-component.html', styl...

Fire after the view has been fully initialized. (Only available for components) import { Component, AfterContentChecked } from '@angular/core'; @Component({ selector: 'so-aftercontentchecked-component', templateUrl: 'aftercontentchecked-component.html', styleUrls: ['aftercontentc...

Fires after initializing both the component view and any of its child views. This is a useful lifecycle hook for plugins outside of the Angular 2 ecosystem. For example, you could use this method to initialize a jQuery date picker based on the markup that Angular 2 has rendered. import { Component,...