Ruby Variableslocal variable | local_variable | instance variable | @instance_variable | class variable | @@class_variable | global variable | $global_variable |
Ruby Data TypesString | "Sequence of characters." or 'Sequence of characters.'
| Symbol (identifier) | :a_symbol, :another_symbol, :name
| Integer | 42, 100, 1002, -256
| Float (floating point) | 1.1, 3.1415926, 5.5, -128.6
| Numeric Methods | +, -, *, /, %
| Comparison Operators | ==, !=, >, >=, <, <=
| Return Value | Last line of a ruby method/block/expression in IRB | Boolean | true or false
| nil
| counts as false in Ruby, everything counts as true | Array (0 indexed) | letters = ["a", "b", "c"]
| letters[2]
| #returns "c" | letters[1] = "monkey"
| ["a", "monkey", "c"]
|
ERBERB | Embedded Ruby for making dynamic HTML templates | erb :hello
| Sinatra looks in "views" folder for hello.erb file | Show @tweets | <% if @tweets %> <% @tweets.each do |tweet| %> <p><%= tweet %></p> <% end %> <% end %> | Instance Variables | Any instance variables you declare in your routes, will be accessible in these erb files |
Ruby Expressionsseen_it = "seen again"
| Save string to variable | num = 3
| Save integer to variable | other_num = 5
| Save another integer to another variable | answer = (num + other_num) * 6
| Save result of adding/multiplying. |
String Interpolationdog_speak = "woof!"
| puts "Dogs say #{dog_speak}"
| or | puts "Dogs say " + dog_speak
|
Conditionalsif/else | if input == admin_password
| | | admin_logged_in = true
| | | else
| | | puts "Sorry, wrong password."
| | | end
|
Useful Ruby Methodssplit
| Breaks a string into an array. | join
| Takes an array and joins into a string. | upcase
| Makes characters capital letters. | reverse
| Reverse characters in a string. | sample
| Randomly choose element. | map
| Do the same thing to every element. |
ResearchCmd+Click (Mac) or Ctrl+Click | Open links in new tabs. | ruby-doc.org ("The Ruby Docs") | Ruby coding best practices. | Stack Overflow | Oops. Research your error. | Guides and blog posts | Has someone done this before? |
| | SinatraSinatra | Framework for building a web server written in Ruby | Routing | Action taken in response to request | Path | text and slashes after domain | http://localhost:4567/hello | Sinatra looks for get '/hello' | | | get '/hello' do
| | | #code to return a response to the browser
| | | end
| String Response | get '/hello'
| | | "Hello, friendly web traveler!"
| | | end
| HTML File Response | get '/hello' do
| | | erb :hello
| | | end
| Get tweets route | get '/' do
| | | @tweets = $client.user_timeline.map { |tweet| tweet.text }
| | | erb :index
| | | end
| Redirect '/'
| Get server to run code in get '/' route |
Array Methodspush
| Add to end of array: letters << "elephant" or letters.push("elephant") | <<
| Shovel operator. Push to end of array. | unshift
| Add element to beginning of array: letters.unshift("zebra") | pop
| Remove from end of array. letters.pop | shift
| Remove from start of array. letters.shift | .method(arguments)
| Call a method with arguments. Some methods require no arguments. | letters.pop
| Method without arguments. |
HashesInstantiate a Hash (hash rockets) | person = {:name => "Lauren", :age => 89, :sex => "female"}
| Instantiate a Hash (shortcut) | person = {name: "Lauren", age: 89, sex: "female"}
| Access value by key. | person[:name] # returns "Lauren"
| Update value by key. | person[:age] = 12
| Insert key, value pair. | person[:gender] = "cis female"
| Remove value by key. | person.delete(:sex) # returns "female"
|
MethodsGreeting Method Accepts Name | def create_greeting(name)
| | | return "Welcome, #{name}"
| | | end
| Call Greeting Method | create_greeting("Lauren")
| | | #returns 'Welcome, Lauren"
| Upcase On Call To Greeting Method | create_greeting("Lauren").upcase
| Arguments | Input given to methods. | Parameters | Define what can be passed to a method. | Return value | Output from a function | Implicit Return | Returning last line of method without explicit "return" |
| | Command LineRuby gems | Download, install, and use ruby software packages on your system | $ ruby -v
| Get Ruby Version | $ irb
| Load up interactive Ruby | $ gem install sinatra
| Install sinatra gem | $ gem install twitter
| Install twitter gem | $ ruby server.rb
| Tell Ruby interpreter to run code. | Ctrl+C | Stop server from running. |
Web and HTTPServer | has IP address, processes requests made by the (client) browser | HTTP | protocol enabling communication between clients and servers | HTTP Verbs | GET, POST, PUT, PATCH, DELETE
| GET | Request Tweets(data) from Twitter API | POST | Submit Tweet(data) to Twitter API | https: | scheme | twitter.com | domain | lauren_n_roth/status/699996428429561856 | path | Params hash | params[:tweet]
|
Loopstimes | 10.times do
| | | puts "Hello!"
| | | end
| times loop with counter | 10.times do |counter|
| | | puts "#{counter}"
| | | end
| each
| letters = ["a", "b", "c"]
| | | letters.each do |letter|
| | | puts "Letter #{letter}"
| | | end
| map
| capital_letters = letters.map do |letter|
| | | letter.upcase
| | | end
| block style | letters.each { |letter| puts "Upcase #{letter.upcase}!" }
| elegant map method | capitals = letters.map { |letter| letter.upcase }
|
Twitter APIDownload files | bit.ly/dbc-twitter-sinatra | Sign Up To Use Twitter API | apps.twitter.com | Create New App | 1. Create new App 2. Create Access Tokens 3. Ensure permissions are read/write | Set up Twitter $client global variable | require twitter
| | | $client = Twitter::REST::Client.new do |config|
| | | config.consumer_key = "YOUR_CONSUMER_KEY" config.consumer_secret = "YOUR_CONSUMER_SECRET" config.access_token = "YOUR_ACCESS_TOKEN" config.access_token_secret = "YOUR_ACCESS_SECRET"
| | | end
| Get user timeline | $client.user_timeline
| Send tweet | $client.update("omg I am tweeting from the command line. So cool!")
|
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