shinokada

a = [[1, 2, 'apple'], [2, 6, 'banana'], [3, 10, 'egg']]
for no, num, item in a
  p "Shopping list #{no}: #{num} #{item}"
end

shinokada

@data = [
  ["M"  , 1000],
  ["CM" , 900],
  ["D"  , 500],
  ["CD" , 400],
  ["C"  , 100],
  ["XC" ,  90],
  ["L"  ,  50],
  ["XL" ,  40],
  ["X"  ,  10],

shinokada

# strange splat
[*0..9]  # [1,2,3,4,5,6,7,8,9]

# http://endofline.wordpress.com/2011/01/21/the-strange-ruby-splat/
# splat creates an array
first, *list = [1,2,3,4]          # first= 1, list= [2,3,4]
*list, last  = [1,2,3,4]          # list= [1,2,3], last= 4
first, *center, last = [1,2,3,4]  # first= 1, center= [2,3], last=4

a = *"Hello"  #=> ["Hello"]

shinokada

[1,2,3,4].inject(:+) # 10
[1,2,3,4].inject:+   # 10

shinokada

#!/usr/bin/ruby
# http://zetcode.com/lang/rubytutorial/io/
$stdout = File.open "output.log", "a" # redirect a standard output to a log file.
puts "Ruby"
puts "Java"
$stdout.close
$stdout = STDOUT # Use predefined standard constant STDOUT to recreate the normal standard output
puts "Python"

shinokada

# http://batsov.com/articles/2013/12/04/using-rubys-each-with-object/
nums = [1, 1, 2, 3, 3, 5]
nums.each_with_object(Hash.new(0)) { |e, a| a[e] += 1 }
# => {1=>2, 2=>1, 3=>2, 5=>1}

nums = [1, 1, 2, 3, 3, 5]
nums.reduce(Hash.new(0)) { |a, e| a[e] += 1; a }
# => {1=>2, 2=>1, 3=>2, 5=>1}

shinokada

# http://blog.flatironschool.com/post/35154441787/rubys-each-with-object

hash = {}
['red', 'green', 'blue'].each do |color|
  hash[color] = 'primary'
end

# Using inject, we don't have to initialize the hash ahead of time

['red', 'green', 'blue'].inject({}) do |hash, color|

shinokada

# I struggled how to add input data to an array in a hash value and these art some
# ways to do. [See more examples](http://judge.u-aizu.ac.jp/onlinejudge/solution.jsp?pid=0105#6).

#Using an array hash[word] = [page.to_i]
# and using has_key?
hash = {}
while n = gets
  word, page = n.split
  hash.has_key?(word) ?  hash[word] << page.to_i :  hash[word] = [page.to_i]
end

shinokada

r = 10..1
p (r.first).downto(r.last).to_a
# [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

p (1..10).reverse_each.to_a
# [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

shinokada

var galleryApp = galleryApp || {};
// perform similar check for nested children

galleryApp.routers = galleryApp.routers || {};
galleryApp.model = galleryApp.model || {};
galleryApp.model.special = galleryApp.model.special || {};
// routers
galleryApp.routers.Workspace = Backbone.Router.extend({});
galleryApp.routers.PhotoSearch = Backbone.Router.extend({});
// models