JunichiIto

str = "no ruby no life" #=> count as {"no"=>2,"ruby"=>1,"life"=>1}

Hash[str.scan(/\w+/).group_by{|s|s}.map{|k,v|[k,v.size]}]

str.scan(/\w+/).each_with_object(Hash.new(0)){|s,h|h[s]+=1}

# require Ruby 2.1.1
str.scan(/\w+/).group_by{|s|s}.map{|k,v|[k,v.size]}.to_h

JunichiIto

def count_by_word(string)
  string
    .scan(/\w+/)
    .group_by{|s| s}
    .map{|word, words| [word, words.size]}
    .to_h # require Ruby 2.1 or higher
end

describe "count by word" do
  it "counts by word" do

JunichiIto

def count_by_word(string)
  string
    .scan(/\w+/)
    .each_with_object(Hash.new(0)){|s, h| h[s] += 1 }
end

JunichiIto

def count_by_word(string)
  fn = ->(s, h){ h[s] += 1 }
  string
    .scan(/\w+/)
    .each_with_object(Hash.new(0), &fn)
end

JunichiIto

user = User.find params[:id]

older_user = User.where("date_of_birth <= ? AND id <> ?", user.date_of_birth, user.id).order("date_of_birth DESC, id").limit(1).first

younger_user = User.where("date_of_birth >= ? AND id <> ?", user.date_of_birth, user.id).order("date_of_birth ASC, id").limit(1).first

JunichiIto

(define (total_count_for amount)
  (+ amount (/ (abs (pred amount)) 2)))

JunichiIto

# coding: utf-8

class KaraokeMachine
  def initialize(melody)
  end

  def transpose(amount)
    "" # これは仮実装なので消してください
  end
end

JunichiIto

This list is based on aliases_spec.rb.

You can see also Module: RSpec::Matchers API.

matcher	aliased to	description
a_truthy_value	be_truthy	a truthy value
a_falsey_value	be_falsey	a falsey value
be_falsy	be_falsey	be falsy
a_falsy_value	be_falsey	a falsy value

JunichiIto

class Event < ActiveRecord::Base
  has_many :groups

  # reference: http://guides.rubyonrails.org/association_basics.html#self-joins
  has_many :next_events, class_name: "Event", foreign_key: "previous_event_id"
  belongs_to :previous_event, class_name: "Event"
end

# schema.rb
  create_table "events", force: :cascade do |t|

JunichiIto

# Gemfile
source 'https://rubygems.org'


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.0'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'