Ruby

goto /users/tim/code/ruby

rails new appname

sets up directory system

bundle install

installs gems

.gitignore

installed with rails new

git init

starts new repository

git add .

git status; tells you what branch you are on and if you have stuff to commit

git commit

commits change locally

git log

of commits

on github

new repository

back on local machine

git remote add origin git@github.com

mckennatim/rubyapp2.git: this line is given in github

git push -u origin master

get checkout -b modify-README

creates a new branch

mate README

now in new branch

git mv README README.markdown

mate README.markdown

git commit -am "improve readme"

commit locally all, message

git checkout master

moves back to master branch

git merge modify-README

bringes changes of the modify-README branch into the master branch

git push

all you need to push it back to github

to use hosting site

heroku

heroku keys:add

heroku create

git push heroku master

git mergetool

to resolve conflicts

heroku wouldn't work with ror3

fixed config/application.rb to read..

require File.expand_path('../boot', __FILE__)

# Pick the frameworks you want:
#require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"

if defined?(Bundler)
  # If you precompile assets before deploying to production, use this line
  Bundler.require(*Rails.groups(:assets => %w(development test)))
  # If you want your assets lazily compiled in production, use this line
  # Bundler.require(:default, :assets, Rails.env)
end
require "active_record"

kill rail server; lsof -wni tcp

3000, kill -9 PID

ruby syntax

>> nil.empty?
NoMethodError: You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.empty?
>> nil.to_s.empty?      # Message chaining
=> true

It’s worth noting that the nil object is special, in that it is the only Ruby object that is false in a boolean context, apart from false itself:

>> if nil
>>   true
>> else
>>   false        # nil is false
>> end
=> false

# 0 (and everything other than nil and false itself) is true

>>  "foo bar     baz".split     # Split a string into a three-element array
=> ["foo", "bar", "baz"]
>> "fooxbarxbazx".split('x')
=> ["foo", "bar", "baz"]

>> a.sort
=> [8, 17, 42]
>> a.reverse
=> [17, 8, 42]
>> a.shuffle
=> [17, 42, 8]


>> a.push(6)                  # Pushing 6 onto an array
=> [42, 8, 17, 6]
>> a << 7                     # Pushing 7 onto an array
=> [42, 8, 17, 6, 7]
>> a << "foo" << "bar"        # Chaining array pushes
=> [42, 8, 17, 6, 7, "foo", "bar"]

>> a
=> [42, 8, 17, 7, "foo", "bar"]
>> a.join                       # Join on nothing
=> "428177foobar"
>> a.join(', ')                 # Join on comma-space
=> "42, 8, 17, 7, foo, bar"

Closely related to arrays are ranges, which can probably most easily be understood by converting them to arrays using the to_a method:

>> 0..9
=> 0..9
>> 0..9.to_a              # Oops, call to_a on 9
NoMethodError: undefined method `to_a' for 9:Fixnum
>> (0..9).to_a            # Use parentheses to call to_a on the range
=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>> a = %w[foo bar baz quux]         # Use %w to make a string array.
=> ["foo", "bar", "baz", "quux"]
>> a[0..2]
=> ["foo", "bar", "baz"]

Ranges also work with characters:

>> ('a'..'e').to_a
=> ["a", "b", "c", "d", "e"]

>> 3.times { puts "Betelgeuse!" }   # 3.times takes a block with no variables.
"Betelgeuse!"
"Betelgeuse!"
"Betelgeuse!"
=> 3
>> (1..5).map { |i| i**2 }          # The ** notation is for 'power'.
=> [1, 4, 9, 16, 25]
>> %w[a b c]                        # Recall that %w makes string arrays.
=> ["a", "b", "c"]
>> %w[a b c].map { |char| char.upcase }
=> ["A", "B", "C"]

>> ('a'..'z').to_a.shuffle[0..7]       # Pull out the first eight elements.
=> ["f", "w", "i", "a", "h", "p", "c", "x"]
>> ('a'..'z').to_a.shuffle[0..7].join  # Join them together to make one string.
=> "mznpybuj"
irb(main):012:0> ('a'..'z').to_a[0..7]
=> ["a", "b", "c", "d", "e", "f", "g", "h"]

>> params[:user] = { :name => "Michael Hartl", :email => "mhartl@example.com" }
=> {:name=>"Michael Hartl", :email=>"mhartl@example.com"}
>> params
=> {:user=>{:name=>"Michael Hartl", :email=>"mhartl@example.com"}}
>>  params[:user][:email]
=> "mhartl@example.com"

>> flash = { :success => "It worked!", :error => "It failed. :-(" }
=> {:success=>"It worked!", :error=>"It failed. :-("}
>> flash.each do |key, value|
?>   puts "Key #{key.inspect} has value #{value.inspect}"
>> end
Key :success has value "It worked!"
Key :error has value "It failed. :-("

>> p :name             # Same as 'puts :name.inspect'
:name

# Parentheses on function calls are optional.
stylesheet_link_tag('blueprint/screen', :media => 'screen')
stylesheet_link_tag 'blueprint/screen', :media => 'screen'

Let’s make a Word class with a palindrome? method that returns true if the word is the same spelled forward and backward:

>> class Word
>>   def palindrome?(string)
>>     string == string.reverse
>>   end
>> end
=> nil

We can use it as follows:

>> w = Word.new              # Make a new Word object.
=> #<Word:0x22d0b20>
>> w.palindrome?("foobar")
=> false
>> w.palindrome?("level")
=> true