orend

[1, 2, 3] * ' '

orend

p (1..10).inject(:*) # instead of: inject(&:*)

# case on ranges
age = rand(1..100)
p age
case age
when -Float::INFINITY..20
  puts "You're too young."
when 21..64

orend

type Word = String
type Sentence = List[Word]
type Occurrences = List[(Char, Int)]
val dictionary: List[Word] = loadDictionary

def wordOccurrences(w: Word): Occurrences = w.toLowerCase().toList.groupBy(x => x).mapValues(x=>x.length).toList.sorted

  /** Converts a sentence into its character occurrence list. */
  def sentenceOccurrences(s: Sentence): Occurrences = wordOccurrences((s foldLeft "") (_ + _))

orend

odobzinski:~/lib/pelusa  $ /Users/odobzinski/.rbenv/versions/rbx-2.0.0-rc1/1.9/bin/pelusa ~/dev_exclusions/assistly/lib/es_search/agent_builder.rb 
  ϟ Pelusa ϟ
  ----------
  /Users/odobzinski/dev_exclusions/assistly/lib/es_search/agent_builder.rb

  class TokenItem
    ✿ Is below 50 lines ✓
    ✿ Uses less than 3 ivars ✗
	This class uses 3 instance variables: @token, @type, @value.
    ✿ Respects Demeter law ✗

orend

f = proc{|string, num, x| x % num == 0 ? string : x}.curry
f3 = f.('Fizz',3)
f15 = f.('FizzBuzz',15)
f5 = f.('Buzz',5)
puts (1..100).map(&f15).map(&f5).map(&f3)

# and here's another approach

module Enumerable
  # map all elements for which the condition is true, leave the rest intact

orend

#Practical Object Oriented Design in Ruby

Design that anticipate specific future requirements almost always end badly.
Practical design does not anticipate what will happen to your application, it merely accepts that something
will and that, in the present, you cannot know what. It does not guess the future; it preserves your options for accommodating the future.
It doesn't choose; it leaves you room to move.
The purpose of design it to allow you to do it later and its primary goal is to reduce the cost of change.

Design is more the art of preserving changeability than it is the act of achieving perfection.

orend

require 'csv'

def memstats
  size = `ps -o size= #{$$}`.strip.to_i
end

memstats #4900
CSV.open('visitors.csv', headers: true) do |csv|
	visitors = csv.each # Enumerator
	memstats # 5164

orend

# a default value of array allows us to implicitly initialize accessed fields
h = Hash.new{ |h ,k| h[k] = []}
h['a'] << "c"
h['a'] << "d"

>> h
{
  "a" => [
    [0] "c",
    [1] "d"

orend

before: 

<%= if profile.has_experience? && profile.experience_public? %>
  <p><strong>Experience:</strong> <%= user_profile.experience %></p>
<% end %>

//after

<h2><%= user_profile.full_name %></h2>
<%= user_profile.bio_html %>

orend

def age(with_respect_to = Time.now)
  ...
end