Oh, Ruby, I Review You

 **Class and Instance Methods** Ruby is made up of objects. Methods allow objects to function and return values. Basically, a method calls for an action or function to happen within an instance or a class. Classes are also objects and a **Class Method** provides functionality to the Class. An *Instance Method *does the same, but for an instance, not for the class. A **Class Method** should be composed when the action you are going for does not apply to an instance of that class. When creating a class method, the self keyword is needed; this is how we know we are defining a class method. This is a class method example from the user model of my Sinatra App portfolio project: def self.username_check(username) self.all.detect do |user| user.username == username end end The "self" keyword sets up this method so that it applies to the scope of the user class. Think of "class" as an actual classroom. There are several students in one classroom and all of them want to sign up for a classroom provided email account. However, the system is set up to prevent more than one student to create a username that has been chosen by another student, no repeats. In order to create a method that will prevent this from happening, as applies to the entire classroom, we create a class method. Now, within this classroom, we have several students who want to access individual subjects for studyhall. Each of those individual subjects within the classroom would be a new instance. For this, we would create **Instance Methods**. class Classroom def subject_one puts "science" end def subject_two puts "art" end def subject_three puts "history" end def subject_four puts "literature" end end ________________________________________________________________________________________________________ Helper Methods. are another type of method and are created to reduce the writing of excess code. They "help" us by providing shortcuts. Helper methods are written in the controller and are accessible in the views. You can also create a separate helper file in the directory and place your helper class methods there. Here is an example of helper methods from my Sinatra App portfolio project from the application controller: helpers do def logged_in? !!session[:user_id] end def current_user User.find(session[:user_id]) end def redirect_if_not_logged_in unless logged_in? redirect to "/login" end end Let's look at the last helper method. How would we call this helper method? Let's look at this code from the Things controller of my project: get '/things' do redirect_if_not_logged_in @things = Thing.all erb :'/things/things' end get '/things/new' do if logged_in? erb :'/things/new' else redirect to "/login" end end In the first section "get '/things' do", you can see how the helper method "redirect_if_not_logged_in" allowed our code to be crisp and to the point without excess data. The helper was called in the second line of the code and we did not have to include all the extra code in the " get '/things/new' do". We could fix this by using the same helper method here: get '/things/new' do redirect_if_not_logged_in erb :'/things/new' end **Dot Notation** <br> One of the coolest and most convenient things ever is dot notation. This allows us to assign a task to an object within a method by simply applying a dot. Let's look at more code from my Sinatra app portfolio project: delete '/things/:id/delete' do @thing = Thing.find(params[:id]) if @thing.user_id == current_user.id @thing.delete erb :'/things/show' end redirect to "/things" end The receiving object is the word before the dot and the message is the word that follows. In the second line, "Thing" is the receiving object and "find" is the message being sent to "Thing". In the third line "delete" is the message and "@thing" is the receiver. Once an object has been established, you can use a dot notation to assign a task to it. In the above example, the third line shows how the dot notation can be used with the objects identifier "user_id". The dot notation is a handy little friend to play with when creating code. **Attributes, Readers, Writers, Accessors Shortcuts >> Getter and Setter Methods** The specific properties of an object are called attributes. To review, methods provide the functionality of the object. Here is an example of code from my CLI Data Gem portfolio project: class Niche_TS::School @@all = [] attr_accessor :name, :rank, :location, :acceptance_rate, :cost, :description, :url def self.all @@all end end In the above code, the attributes are name, rank, location, acceptance rate, cost, description and url. This attribute accessor method displays a list of attributes for the object school class. You can also use the attribute writer to create setter methods and attribute reader to create getter methods. In addition, you can create getter methods yourself: class Student def initialize(name) @name = name end def name # this creates getter method for name @name end end Zelda = Student.new('Zelda') zelda.name # this calls getter method and returns "Zelda" **The Initialize Method** To complete the code from before: class Niche_TS::School @@all = [] attr_accessor :name, :rank, :location, :acceptance_rate, :cost, :description, :url def self.all @@all end def initialize(name=nil, rank=nil, location=nil, acceptance_rate=nil, cost=nil, url=nil, description=nil) @name = name @rank = rank @location = location @acceptance_rate = acceptance_rate @cost = cost @url = url @description = description @@all << self end def self.find_by_rank(search_rank) all.each do |school| if school.rank.gsub("#", "") == search_rank return school end end end end If we want each instance of our class to include our attributes, an initialize method must be defined. The name variable above has the name attribute assigned in the line "@name =name". Now when we can call on "school.rank, school.name, school.cost" and so on. **Parentheses and (Arguments/Parameters)** The general rule is you use parentheses for most (there are a couple of exceptions) method calls that take arguments. The difference between params or parameters and arguments can be confusing if you think about too much. They both can use parentheses and there are many more complex ideas to spend more time on than this one. def method(args) end This is an example from the strong params lesson from Flatiron: def create @post = Post.new(post_params(:title, :description)) @post.save redirect_to post_path(@post) end def update @post = Post.find(params[:id]) @post.update(post_params(:title)) redirect_to post_path(@post) end private def post_params(*args) params.require(:post).permit(*args) end **Square Brackets [ ] ** and **Curly Brackets { } ** In Ruby, I have come across *Square Brackets* when: 1) defining arrays: Letters = [a, b, c, d...] 2) accessing the elements inside arrays and hashes. 3) In Sinatra, for dynamic routing. get '/things/:id/edit' do @thing = Thing.find(params[:id]) if @thing.user_id == session[:user_id] erb :'/things/edit' else redirect to "/login" end end Square brackets also are still just accessing elements inside of a hash because `params` and `session` both are hashes. *Curly Braces * Curly braces are usually found surrounding hashes and can also surround blocks. my_hash = {:a => 1, :b => 2, :c => 3} In conclusion, this blog was meant to be a review to think out loud, and make sure I understand what the "H" I am doing. It is easy to take for granted that when studying and doing the readme lessons and code-a-longs that you will remember everything. This hasn't been the case for me. It is easy to forget. There is so much information to grasp, learn and build on. When I get stuck, I take a break. If I force myself to keep working with spots in my eyes, it creates a bigger mess of code and I get really lost or I learn incorrectly. If I take a break, sometimes for the entire night and start fresh later, I usually get it pretty quickly. Also, I have learned that this is not easy. So I have stopped beating myself up. It is okay to struggle with learning difficult things. The important thing is not to give up. Lastly, This is really fun. I actually love the challenge and I think one day, I will be an expert. My hope anyway!