The Treasures of Ruby, one for each day

Christophe Philemotte, Paris.rb, 6 May 2013

About me

• Developer (@toch on GitHub, @_toch on Twitter)

• Author on blog.8thcolor.com

• CoFounder of PullReview https://pullreview.com

I hope to see Ruby help every programmer in the world to be productive, and to
enjoy programming, and to be happy. That is the primary purpose of Ruby
language. Matz, 2008

contacts = %w[Granny Bill]
contacts << 'Granny' unless contacts.include? 'Granny'

tags_post1 = [ 'ruby', 'rails', 'test' ]
tags_post2 = [ 'test', 'rspec' ]

common_tags = []
tags_post1.each { |tag| common_tags << tag if tags_post2.include? tag }

String: How to remove accents and diacritics?

keyword = 'Kurt Gödel'

keyword = 'Kurt Gödel'

keyword.tr(
  "ÀÁÂÃÄÅàáâãäåĀāĂ㥹ÇçĆćĈĉĊċČčÐðĎďĐđÈÉÊËèéêëĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħÌÍÎÏìíîïĨĩĪīĬĭĮįİıĴĵĶķĸĹĺĻļĽľĿŀŁłÑñŃńŅņŇňʼnŊŋÒÓÔÕÖØòóôõöøŌōŎŏŐőŔŕŖŗŘřŚśŜŝŞşŠšſŢţŤťŦŧÙÚÛÜùúûüŨũŪūŬŭŮůŰűŲųŴŵÝýÿŶŷŸŹźŻżŽž",
  "AAAAAAaaaaaaAaAaAaCcCcCcCcCcDdDdDdEEEEeeeeEeEeEeEeEeGgGgGgGgHhHhIIIIiiiiIiIiIiIiIiJjKkkLlLlLlLlLlNnNnNnNnnNnOOOOOOooooooOoOoOoRrRrRrSsSsSsSssTtTtTtUUUUuuuuUuUuUuUuUuUuWwYyyYyYZzZzZz"
)

keyword = 'Kurt Gödel'

require 'active_support/inflector' # not necessary if Rails

ActiveSupport::Inflector.transliterate('Kurt Gödel')

specific rules into locales/de.yml

i18n:
  transliterate:
    rule:
      ü: "ue"
      ö: "oe"

String: How to clean up invalid byte sequences?

ArgumentError: invalid byte sequence in UTF-8

line = "This is an invalid byte sequence \244"


line.upcase

ArgumentError: invalid byte sequence in UTF-8

line = "This is an invalid byte sequence \244"
line.encode!('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')

line.upcase

line = "This is an invalid byte sequence \244"
line.scrub!('') # gem 'string-scrub' if < 2.1

line.upcase

Array: How to avoid duplicates in an Array?

contacts = %w[Granny Bill]
contacts << 'Granny' unless contacts.include? 'Granny'

contacts = %w[Granny Bill]
contacts << 'Granny'
contacts.uniq!

require 'set'
contacts = Set.new(%w[Granny Bill])
contacts << 'Granny'

Array: How to find what elements are common to 2 Arrays?

tags_post1 = [ 'ruby', 'rails', 'test' ]
tags_post2 = [ 'test', 'rspec' ]

common_tags = []
tags_post1.each { |tag| common_tags << tag if tags_post2.include? tag }

tags_post1 = [ 'ruby', 'rails', 'test' ]
tags_post2 = [ 'test', 'rspec' ]

common_tags = tags_post1 & tags_post2

Hash: How to filter out some keys of a Hash?

histogram = {
  monday: 5,
  tuesday: 7,
  wednesday: 10,
  thursday: 18,
  friday: 7,
  saturday: 2,
  sunday: 0
}

histogram = histogram.select { |k, _| k != :saturday && k != :sunday }

def filter(hsh, *keys)
  hsh.select { |k, _| !keys.include? k }
end

filter(histogram, :saturday, :sunday)

def filter(hsh, *keys)
  hsh.reject { |k, _| keys.include? k }
end

filter(histogram, :saturday, :sunday)

require 'active_support/core_ext/hash' # not necessary if Rails

histogram.except(:saturday, :sunday)

Hash: How to find the differences between two Hashes?

entries = {
  1372284000 => "CVE-2013-4073",
  1368482400 => "CVE-2013-2065"
}

updated_entries = {
  1385074800 => "CVE-2013-4164",
  1372284000 => "CVE-2013-4073",
  1368482400 => "CVE-2013-2065"
}

new_entries = updated_entries.reject { |k, _| entries.include? k }

1. Read the doc: yes, the full page

• Ruby Doc http://ruby-doc.org/

• Rails Doc http://api.rubyonrails.org/

• Apidock http://apidock.com/

• OmniRef https://www.omniref.com/

2. Read the source, Luke

• Gem source

• Rails source https://github.com/rails/rails

3. SO, Google

4. Blogs, Podcasts, Conferences, Meetup…

5. Discuss

• Your coworker/colleague

• A friend

• ME :)