Railsドキュメント(v6.0.2.1)

ApplicationController.helpers.<メソッド名>

ApplicationController.helpers.user_path

変数.nil?

変数.empty?

変数.blank?

変数.present?

@pages = Page.all
if @pages.present?
...
else
puts "no pages"
end

名詞.pluralize([個数, ロケール])

'post'.pluralize
# "posts"

'octopus'.pluralize
# "octopi"

'sheep'.pluralize
# "sheep"

'words'.pluralize
# "words"

'the blue mailman'.pluralize
# "the blue mailmen"

'CamelOctopus'.pluralize
# "CamelOctopi"

'apple'.pluralize(1)
# "apple"

'apple'.pluralize(2)
# "apples"

'ley'.pluralize(:es)
# "leyes"

singularize(文字列 [, ロケーション])

singularize('posts')
# "post"

singularize('octopi')
# "octopus"

singularize('sheep')
# "sheep"

singularize('CamelOctopi')
# "CamelOctopus"

singularize('leyes', :js)
# "ley"

underscore("文字列")

underscore("Product")
# "product"

underscore("AdminUser")
# "admin_user"

underscore("Backoffice::Session")
# "backoffice/session"

camelize(文字列 [, オプション])

camelize('product')
# "Product"

camelize('backoffice/session')
# "Backoffice::Session"

camelize('active_record'. :lower)
# "activeRecord"

tableize(文字列)

tableize("Page")
# "pages"

tableize("AdminUser")
# "admin_users"

classify(テーブル名)

classify("people")
# "Person"

日付.tomorrow

Date.new(2011, 12, 24).tomorrow
#  Sun, 25 Dec 2011

Date.new(2011, 12, 24) + 1
#  Sun, 25 Dec 2011

日付.yesterday

Date.new(2011, 12, 24).yesterday
#  Fri, 23 Dec 2011

Date.new(2011, 12, 24) - 1
#  Fri, 23 Dec 2012

日付.prev_year

Date.new(2011, 12, 24).prev_year
#  Fri, 24 Dec 2010

Date.new(2011, 12, 24) << 12
#  Fri, 24 Dec 2010

日付.next_year

Date.new(2011, 12, 24).next_year
#  Mon, 24 Dec 2012

Date.new(2011, 12, 24) >> 12
#  Mon, 24 Dec 2012

日付.prev_month

Date.new(2011, 12, 24).prev_month
# Thu,  24 Nov 2011

Date.new(2011, 12, 24) << 1
# Thu, 24 Nov 2011

日付.next_month

Date.new(2011, 12, 24).next_month
# Tue,  24 Jan 2012

Date.new(2011, 12, 24) >> 1
#  Tue, 24 Jan 2012

日付.beginning_of_week

Date.new(2011, 12, 24).beginning_of_week
# Mon, 19 Dec 2011

日付.end_of_week

Date.new(2011, 12, 24).end_of_week
# Sun, 25 Dec 2011

日付.next_week

Date.new(2011, 12, 24).next_week
# Mon, 26 Dec 2011

Date.new(2011, 12, 24).next_week(:saturday)
# Sat, 31 Dec 2011

日付.prev_week

Date.new(2011, 12, 24).prev_week
# Mon, 12 Dec 2011

Date.new(2011, 12, 24).prev_week
# Sat, 17 Dec 2011

日付.beginning_of_month

Date.new(2011, 12, 24).beginning_of_month
# Thu, 01 Dec 2011

日付.end_of_month

Date.new(2011, 12, 24).end_of_month
# Sat, 31 Dec 2011

日付.beginning_of_quarter

Date.new(2011, 12, 24).beginning_of_quarter
# Sat, 01 Oct 2011

日付.end_of_quarter

Date.new(2011, 12, 24).end_of_quarter
# Sat, 31 Dec 2011

日付.beginning_of_year

Date.new(2011, 12, 24).beginning_of_year
# Sat, 01 Jan 2011

日付.end_of_year

Date.new(2011, 12, 24).end_of_year
# Sat, 31 Dec 2011

日付.years_ago(年数)

Date.new(2011, 12, 24).years_ago(10)
# Mon, 24 Dec 2001

日付.years_ago(年数)

Date.new(2011, 12, 24).years_ago(10)
# Mon, 24 Dec 2001

日付.years_since(年数)

Date.new(2011, 12, 24).years_since(10)
# Fri, 24 Dec 2021

日付.months_ago(月数)

Date.new(2011, 12, 24).months_ago(2)
# Mon, 24 Oct 2011

日付.months_since(月数)

Date.new(2011, 12, 24).months_since(2)
# Fri, 24 Feb 2012

日付.weeks_ago(週数)

Date.new(2011, 12, 24).weeks_ago(2)
# Sat, 10 Dec 2011

日付.advance(日付のハッシュ)

Date.new(2011, 12, 24).advance(months: 2, days: -2)
# Wed, 22 Feb 2011

日付.change(日付のハッシュ)

Date.new(2011, 12, 24).change(months: 2, days: -2)
# Sat, 24 Dec 2011

日付 (+ or -) 日付

Date.new(2011, 12, 24) + 2.day
# Mon, 26 Dec 2011

Date.new(2011, 12, 24) - 1.year
# Fri, 24 Dec 2010

日付.beginning_of_day

Date.new(2011, 12, 24).beginning_of_day
# Sat, 24 Dec 2011 00:00:00 JST +09:00

日付.beginning_of_hour

Date.new(2011, 12, 24, 10, 55, 55).beginning_of_hour
# Sat, 24 Dec 2011 10:00:00 JST +09:00

日付.end_of_day

Date.new(2011, 12, 24).end_of_day
# Sat, 24 Dec 2011 23:59:59 JST +09:00

日付.ago(秒数)

Date.new(2011, 12, 24).ago(1)
# Sat, 23 Dec 2011 23:59:59 JST +09:00

日付.since(秒数)

Date.new(2011, 12, 24).since(1)
# Sat, 24 Dec 2011 00:00:01 JST +09:00

日時.tomorrow

DateTime.new(2011, 12, 24, 00, 00, 00).tomorrow
#  Sun, 25 Dec 2011 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00) + 1
#  Sun, 25 Dec 2011 00:00:00 +0000

日時.yesterday

DateTime.new(2011, 12, 24).yesterday
#  Fri, 23 Dec 2011 00:00:00 +0000

DateTime.new(2011, 12, 24) - 1
#  Fri, 23 Dec 2011 00:00:00 +0000

日時.prev_year

DateTime.new(2011, 12, 24, 00, 00, 00).prev_year
#  Fri, 24 Dec 2010 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00) << 12
#  Fri, 24 Dec 2010 00:00:00 +0000

日時.next_year

DateTime.new(2011, 12, 24, 00, 00, 00).next_year
#  Mon, 24 Dec 2012 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00) >> 12
#  Mon, 24 Dec 2012 00:00:00 +0000

日時.prev_month

DateTime.new(2011, 12, 24, 00, 00, 00).prev_month
# Thu,  24 Nov 2011 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00) << 1
# Thu,  24 Nov 2011 00:00:00 +0000

日時.next_month

DateTime.new(2011, 12, 24, 00, 00, 00).next_month
# Tue,  24 Jan 2012 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00) >> 1
# Tue,  24 Jan 2012 00:00:00 +0000

日時.beginning_of_week

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_week
# Mon, 19 Dec 2011 00:00:00 +0000

日時.end_of_week

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_week
# Sun, 25 Dec 2011 23:59:59 +0000

日時.next_week

DateTime.new(2011, 12, 24, 00, 00, 00).next_week
# Mon, 26 Dec 2011 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00).next_week(:saturday)
# Sat, 31 Dec 2011 00:00:00 +0000

日時.prev_week

DateTime.new(2011, 12, 24, 00, 00, 00).prev_week
# Mon, 12 Dec 2011 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00).prev_week
# Sat, 17 Dec 2011 00:00:00 +0000

日時.beginning_of_month

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_month
# Thu, 01 Dec 2011 00:00:00 +0000

日時.end_of_month

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_month
# Sat, 31 Dec 2011 23:59:59 +0000

日時.beginning_of_quarter

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_quarter
# Sat, 01 Oct 2011 00:00:00 +0000

日時.end_of_quarter

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_quarter
# Sat, 31 Dec 2011 23:59:59 +0000

日時.beginning_of_year

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_year
# Sat, 01 Jan 2011 00:00:00 +0000

日時.end_of_year

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_year
# Sat, 31 Dec 2011 23:59:59 +0000

日時.years_ago(年数)

DateTime.new(2011, 12, 24, 00, 00, 00).years_ago(10)
# Mon, 24 Dec 2001 00:00:00 +0000

日時.years_since(年数)

DateTime.new(2011, 12, 24, 00, 00, 00).years_since(10)
# Fri, 24 Dec 2021 00:00:00 +0000

日時.months_ago(月数)

DateTime.new(2011, 12, 24, 00, 00, 00).months_ago(2)
# Mon, 24 Oct 2011 00:00:00 +0000

日時.months_since(月数)

DateTime.new(2011, 12, 24, 00, 00, 00).months_since(2)
# Fri, 24 Feb 2012 00:00:00 +0000

日時.weeks_ago(週数)

DateTime.new(2011, 12, 24, 00, 00, 00).weeks_ago(2)
# Sat, 10 Dec 2011 00:00:00 +0000

日時.advance(日時のハッシュ)

DateTime.new(2011, 12, 24, 00, 00, 00).advance(months: 2, days: -2)
# Wed, 22 Feb 2011 00:00:00 +0000

日時.change(日時のハッシュ)

DateTime.new(2011, 12, 24, 00, 00, 00).change(months: 2, days: -2)
# Sat, 24 Dec 2011 00:00:00 +0000

日時 (+ or -) 日時

DateTime.new(2011, 12, 24, 00, 00, 00) + 2.day
# Mon, 26 Dec 2011 00:00:00 +0000

DateTime.new(2011, 12, 24, 00, 00, 00) - 1.year
# Fri, 24 Dec 2010 00:00:00 +0000

日時.beginning_of_day

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_day
# Sat, 24 Dec 2011 00:00:00 +0000

日時.beginning_of_hour

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_hour

日時.beginning_of_minute

DateTime.new(2011, 12, 24, 00, 00, 00).beginning_of_minute

日時.end_of_day

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_day
# Sat, 24 Dec 2011 23:59:59 +0000

日時.end_of_hour

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_hour

日時.end_of_minute

DateTime.new(2011, 12, 24, 00, 00, 00).end_of_minute

日時.ago(秒数)

DateTime.new(2011, 12, 24, 00, 00, 00).ago(1)
# Sat, 23 Dec 2011 23:59:59 +0000

日時.since(秒数)

DateTime.new(2011, 12, 24, 00, 00, 00).since(1)
# Sat, 24 Dec 2011 00:00:01 +0000

日時.seconds_since_midnight

DateTime.new(2011, 12, 24, 10, 00, 00).seconds_since_midnight
# 36000

日時.seconds_since_midnight

DateTime.current.utc # Sat, 24 Dec 2011 00:00:00 +0900
# Fir, 23 Dec 2011 09:00:00 +1500

日時.formatted_offset([コロンの有無])

datetime = DateTime.civil(2000, 1, 1, 0, 0, 0, Rational(-6, 24))
datetime.formatted_offset         # "-06:00"
datetime.formatted_offset(false)  # "-0600"

時間.tomorrow

Time.mktime(2011, 12, 24, 00, 00, 00).tomorrow
#  2011-12-25 00:00:00 +0900

Time.mktime(2011, 12, 24, 00, 00, 00) + 86400
#  2011-12-25 00:00:00 +0900

時間.yesterday

Time.mktime(2011, 12, 24).yesterday
#  2011-12-23 00:00:00 +0900

Time.mktime(2011, 12, 24) - 86400
#  2011-12-23 00:00:00 +0900

時間.prev_year

Time.mktime(2011, 12, 24, 00, 00, 00).prev_year
#  2010-12-24 00:00:00 +0900

Time.mktime(2011, 12, 24, 00, 00, 00) - 31536000
#  2010-12-24 00:00:00 +0900

時間.next_year

Time.mktime(2011, 12, 24, 00, 00, 00).next_year
#  2012-12-24 00:00:00 +0900

Time.mktime(2011, 12, 24, 00, 00, 00) + 31536000
#  2012-12-24 00:00:00 +0900

時間.prev_month

Time.mktime(2011, 12, 24, 00, 00, 00).prev_month
# 2011-11-24 00:00:00 +0900

時間.next_month

Time.mktime(2011, 12, 24, 00, 00, 00).next_month
# 2012-01-24 00:00:00 +0900

時間.beginning_of_week

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_week
# 2011-12-19 00:00:00 +0900

時間.end_of_week

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_week
# 2011-12-25 23:59:59 +0900

時間.next_week

Time.mktime(2011, 12, 24, 00, 00, 00).next_week
# 2011-12-26 00:00:00 +0900

Time.mktime(2011, 12, 24, 00, 00, 00).next_week(:saturday)
# 2011-12-31 00:00:00 +0900

時間.prev_week

Time.mktime(2011, 12, 24, 00, 00, 00).prev_week
# 2011-12-12 00:00:00 +0900

Time.mktime(2011, 12, 24, 00, 00, 00).prev_week
# Sat, 17 Dec 2011 00:00:00 +0000

時間.beginning_of_month

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_month
# 2011-12-01 00:00:00 +0900

時間.end_of_month

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_month
# 2011-12-31  23:59:59 +0900

時間.beginning_of_quarter

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_quarter
# 2011-10-01 00:00:00 +0900

時間.end_of_quarter

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_quarter
# 2011-12-31 23:59:59 +0900

時間.beginning_of_year

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_year
# 2011-01-01 00:00:00 +0900

時間.end_of_year

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_year
# 2011-12-31 23:59:59 +0900

時間.years_ago(年数)

Time.mktime(2011, 12, 24, 00, 00, 00).years_ago(10)
# 2001-12-24 00:00:00 +0900

時間.years_since(年数)

Time.mktime(2011, 12, 24, 00, 00, 00).years_since(10)
# 2021-12-24 00:00:00 +0900

時間.months_ago(月数)

Time.mktime(2011, 12, 24, 00, 00, 00).months_ago(2)
# 2011-10-24 00:00:00 +0900

時間.months_since(月数)

Time.mktime(2011, 12, 24, 00, 00, 00).months_since(2)
# 2012-02-24 00:00:00 +0900

時間.weeks_ago(週数)

Time.mktime(2011, 12, 24, 00, 00, 00).weeks_ago(2)
# Sat, 10 Dec 2011 00:00:00 +0000

時間.advance(時間のハッシュ)

Time.mktime(2011, 12, 24, 00, 00, 00).advance(months: 2, days: -2)
# 2012-02-22 00:00:00 +0900

時間.change(オプション)

Time.mktime(2011, 12, 24, 00, 00, 00).change(months: 2, days: -2)
# 2011-12-24 00:00:00 +0900

時間 (+ or -) 時間

Time.mktime(2011, 12, 24, 00, 00, 00) + 2.day
# 2011-12-26 00:00:00 +0900

Time.mktime(2011, 12, 24, 00, 00, 00) - 1.year
# 2011-12-24 00:00:00 +0900

時間.beginning_of_day

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_day

時間.beginning_of_hour

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_hour

時間.beginning_of_minute

Time.mktime(2011, 12, 24, 00, 00, 00).beginning_of_minute

時間.end_of_day

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_day
# 2011-12-24 23:59:59 +0900

時間.end_of_hour

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_hour

時間.end_of_minute

Time.mktime(2011, 12, 24, 00, 00, 00).end_of_minute

時間.ago(秒数)

Time.mktime(2011, 12, 24, 00, 00, 00).ago(1)
# 2011-12-23 23:59:59 +0900

時間.since(秒数)

Time.mktime(2011, 12, 24, 00, 00, 00).since(1)
# 2011-12-24 00:00:01 +0900

時間.seconds_since_midnight

Time.mktime(2011, 12, 24, 10, 00, 00).seconds_since_midnight
# 36000.0

時間.seconds_since_midnight

Time.current.utc # 2011-12-24 00:00:00 +0900
# 2011-12-23 15:00:00 UTC

時間.zone_default

Time.zone_default
# (GMT+09:00) Tokyo

Time.days_in_month(月 [, 年])

Time.days_in_month(2, 2020)
# 29

Time.days_in_month(2)
# 29

Time.days_in_year(月 [, 年])

Time.days_in_year(2, 2020)
# 365

Time.days_in_year(2)
# 365

Time.find_zone(タイムゾーン)

Time.find_zone "Tokyo"

Time.rfc3339(文字列)

Time.rfc3339('1999-12-31T14:00:00-10:00')
# 2000-01-01 00:00:00 -1000

Time.use_zone(文字列) {
    処理内容
}

Time.use_zone "Tokyo" {
    Time.local(2019, 01, 01, 00, 00, 00)
}

Time.now.formatted_offset([コロンの有無])

Time.local(2000).formatted_offset
# "-06:00"

Time.local(2000).formatted_offset(false)
# "-0600"

Time.now.middle_of_day

Time.mktime(2011, 12, 24, 00, 00, 00).middle_of_day

Time.now.next_day

Time.mktime(2011, 12, 24, 00, 00, 00).next_day

Time.next_month

Time.mktime(2011, 12, 24, 00, 00, 00).next_month

Time.now.next_year

Time.mktime(2011, 12, 24, 00, 00, 00).next_year

Time.prev_day

Time.mktime(2011, 12, 24, 00, 00, 00).prev_day

Time.now.prev_month

Time.mktime(2011, 12, 24, 00, 00, 00).prev_month

Time.prev_year

Time.mktime(2011, 12, 24, 00, 00, 00).prev_year

Time.now.seconds_since_midnight

Time.mktime(2011, 12, 24, 00, 00, 00).seconds_since_midnight

Time.now.seconds_until_end_of_day

Time.mktime(2011, 12, 24, 00, 00, 00).seconds_until_end_of_day

Time.now.to_formatted_s(フォーマット)

Time.now.to_formatted_s(:time)
# "06:10"

Time.now.to_s(:time)
# "06:10"

Time.now.to_formatted_s(:db)
# "2007-01-18 06:10:17"

Time.now.to_formatted_s(:number)
# "20070118061017"

Time.now.to_formatted_s(:short)
# "18 Jan 06:10"

Time.now.to_formatted_s(:long)
# "January 18, 2007 06:10"

Time.now.to_formatted_s(:long_ordinal)
# "January 18th, 2007 06:10"

Time.now.to_formatted_s(:rfc822)
# "Thu, 18 Jan 2007 06:10:17 -0600"

Time.now.to_formatted_s(:iso8601)
# "2007-01-18T06:10:17-06:00"

数字.bytes

数字.kilobytes

数字.megabytes

数字.gigabytes

数字.terabytes

数字.petabytes

数字.exabytes

2.kilobytes
# 2048

constantize("文字列")

constantize('Module')
# Module

constantize('Test::Unit')
# Test::Unit

dasherize("文字列")
or
文字列.dasherize()

dasherize('puni_puni')
# "puni-puni"

deconstantize("文字列")
or
文字列.deconstantize()

deconstantize('Net::HTTP')
# "Net"

deconstantize('::Net::HTTP')
# "::Net"

deconstantize('String')
# ""

deconstantize('')
# ""

demodulize("文字列")
or
文字列.demodulize()

demodulize('ActiveRecord::CoreExtensions::String::Inflections')
# "Inflections"

demodulize('Inflections')
# "Inflections"

foreign_key(文字列 [, 名前とidの間にアンダーバーを入れるか = true])
or
文字列.foreign_key([名前とidの間にアンダーバーを入れるか = true])

foreign_key('Message')
# "message_id"

foreign_key('Message', false)
# "messageid"

foreign_key('Admin::Post')
# "post_id"

add_foreign_key(テーブル名, 参照先テーブル名 [, オプション])

add_foreign_key :articles, :authors
# ALTER TABLE "articles" ADD CONSTRAINT fk_rails_e74ce85cbc FOREIGN KEY ("author_id") REFERENCES "authors" ("id")

add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id"
# ALTER TABLE "articles" ADD CONSTRAINT fk_rails_58ca3d3a82 FOREIGN KEY ("author_id") REFERENCES "users" ("lng_id")

add_foreign_key :articles, :authors, on_delete: :cascade
# ALTER TABLE "articles" ADD CONSTRAINT fk_rails_e74ce85cbc FOREIGN KEY ("author_id") REFERENCES "authors" ("id") ON DELETE CASCADE

humanize(文字列 [, オプション])

humanize('employee_salary')
# "Employee salary"

humanize('author_id')
# "Author"

humanize('author_id', capitalize: false)
# "author"

humanize('_id')
# "Id"

humanize('author_id', keep_id_suffix: true)
# "Author Id"

number_to_currency(数値 [, オプション])

number_to_currency(123456789)
# $123,456,789.00

number_to_currency(123456789, precision: 5)
# $123,456,789.00000

number_to_currency(123456789, separator: " ")
# $123,456,789 00

number_to_currency(123456789, delimiter: " ")
# $123 456 789.00

number_to_currency(123456789, unit: "￥")
# ￥123,456,789.00

number_to_currency(123456789, format: "%u%n", unit: "￥")
# 123,456,789.00円

number_to_currency(-123456789, negative_format: "%u-%n")
# $-123,456,789.00

# config/locales/jp/yml
jp:
  number:
    currency:
      format:
        unit: "円"
        format: "%n%u"
        negative_format: "-%n%u"
        precision: 0

number_to_currency(123456789, locale: 'jp')
# 123,456,789円

number_to_human(数値 [, オプション])

number_to_human(123456789)
# 123 Million

number_to_human(123456789, precision: 5)
# 123.00 Million

number_to_human(123456789, precision: 5, separator: " ")
# 123 00 Million

number_to_human(123456789, units: {hundred: "百", thousand: "千", million: "百万", billion: "十億", trillion: "兆", quadrillion: "千兆"})
# 123 百万

number_to_human_size(数値 [, オプション])

number_to_human_size 123456789
# 118 MB

number_to_human_size 524288000, precision: 5
# 500 MB

number_to_percentage(数値 [, オプション])

number_to_percentage(100)
# 100.000%

number_with_delimiter(数値 [, オプション])

number_with_delimiter 123456789
# 123,456,789

number_with_delimiter(12345678, delimiter: ".")
# => 12.345.678

number_with_delimiter("112a")
# => 112a

number_with_precision(数値 [, オプション])

number_with_precision(12345678)
# 12,345,678

number_with_precision("123456")
# 123,456

number_with_precision(12345678.05)
# 12,345,678.05

number_with_precision(12345678, delimiter: ".")
# 12.345.678

number_with_precision(12345678.05, separator: " ")
# 12,345,678 05

number_with_precision(12345678.05, locale: :fr)
# 12 345 678,05

number_with_precision("112a")
# 112a

number_with_precision("123456.78", delimiter_pattern: /(\d+?)(?=(\d\d)+(\d)(?!\d))/)
# 1,23,456.78

number_to_phone(数値 [, オプション])

number_to_phone(123456789)
# 123456789.000

number_to_delimited(数値 [, オプション])

number_to_delimited(12345678)
# 12,345,678

number_to_delimited('123456')
# 123,456

number_to_delimited(12345678.05)
# 12,345,678.05

number_to_delimited(12345678, delimiter: '.')
# 12.345.678

number_to_delimited(12345678.05, separator: ' ')
# 12,345,678 05

number_to_delimited(12345678.05, locale: :fr)
# 12 345 678,05

number_to_delimited('112a')
# 112a

number_to_rounded(数値 [, オプション])

number_to_rounded(111.2345)
# 111.235

number_to_rounded(111.2345, precision: 2)
# 111.23

number_to_rounded(13, precision: 5)
# 13.00000

number_to_rounded(389.32314, precision: 0)
# 389

number_to_rounded(111.2345, significant: true)
# 111

number_to_rounded(111.2345, precision: 1, significant: true)
# 100

number_to_rounded(111.234, locale: :fr)
# 111,234

number_to_rounded(1111.2345, precision: 2, separator: ',', delimiter: '.')
# 1.111,23

配列.to_xml([オプション])

ハッシュ.to_xml([オプション])

[{ foo: 1, bar: 2}, { baz: 3}].to_xml
# <?xml version="1.0" encoding="UTF-8"?>
# <objects type="array">
#   <object>
#     <bar type="integer">2</bar>
#     <foo type="integer">1</foo>
#   </object>
#   <object>
#     <baz type="integer">3</baz>
#   </object>
# </objects>

{ foo: 1, bar: 2 }.to_xml
# =>
# <?xml version="1.0" encoding="UTF-8"?>
# <hash>
#   <foo type="integer">1</foo>
#   <bar type="integer">2</bar>
# </hash>

配列.deep_dup

array = [1, [2, 3]]
dup   = array.deep_dup
dup[1][2] = 4
array[1][2] # nil
dup[1][2]   # 4

配列.excluding(要素)

["David", "Rafael", "Aaron", "Todd"].excluding("Aaron", "Todd")
# ["David", "Rafael"]

[ [ 0, 1 ], [ 1, 0 ] ].excluding([ [ 1, 0 ] ])
# [ [ 0, 1 ] ]

配列.excluding!(要素)

["David", "Rafael", "Aaron", "Todd"].excluding!("Aaron", "Todd")
# ["David", "Rafael"]

[ [ 0, 1 ], [ 1, 0 ] ].excluding!([ [ 1, 0 ] ])
# [ [ 0, 1 ] ]

配列.from(位置)

%w( a b c d ).from(0)
# ["a", "b", "c", "d"]

%w( a b c d ).from(2)
# ["c", "d"]

%w( a b c d ).from(10)
# []

%w().from(0)
# []

配列.in_groups(数, 埋める文字列)

%w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|group| p group}
# ["1", "2", "3", "4"]
# ["5", "6", "7", nil]
# ["8", "9", "10", nil]

%w(1 2 3 4 5 6 7 8 9 10).in_groups(3, ' ') {|group| p group}
# ["1", "2", "3", "4"]
# ["5", "6", "7", " "]
# ["8", "9", "10", " "]

配列.in_groups_of(数, 埋める文字列)

%w(1 2 3 4 5 6 7 8 9 10).in_groups_of(3) {|group| p group}
# ["1", "2", "3"]
# ["4", "5", "6"]
# ["7", "8", "9"]
# ["10", nil, nil]

%w(1 2 3 4 5).in_groups_of(2, ' ') {|group| p group}
# ["1", "2"]
# ["3", "4"]
# ["5", " "]

配列.including(要素)

[ 1, 2, 3 ].including(4, 5)
# [ 1, 2, 3, 4, 5 ]

[ [ 0, 1 ] ].including([ [ 1, 0 ] ])
# [ [ 0, 1 ], [ 1, 0 ] ]

配列.inquiry

pets = [:cat, :dog].inquiry
pets.cat?     # true
pets.ferret?  # false

配列.split(値)

[1, 2, 3, 4, 5].split(3)
# [[1, 2], [4, 5]]

(1..10).to_a.split { |i| i % 3 == 0 }
# [[1, 2], [4, 5], [7, 8], [10]]

配列.to(位置)

%w( a b c d ).to(0)
# ["a"]

%w( a b c d ).to(2)
# ["a", "b", "c"]

%w( a b c d ).to(10)
# ["a", "b", "c", "d"]

%w().to(0)
# []

配列.to_query(キー名)

['Rails', 'coding'].to_query('hobbies')
# "hobbies%5B%5D=Rails&hobbies%5B%5D=coding"

配列.to_sentence([オプション])

[].to_sentence
# ""

['one'].to_sentence
# "one"

['one', 'two'].to_sentence
# "one and two"

['one', 'two', 'three'].to_sentence
# "one, two, and three"

配列.to_xml([オプション])

[{ foo: 1, bar: 2}, { baz: 3}].to_xml
# <?xml version="1.0" encoding="UTF-8"?>
# <objects type="array">
#   <object>
#     <bar type="integer">2</bar>
#     <foo type="integer">1</foo>
#   </object>
#   <object>
#     <baz type="integer">3</baz>
#   </object>
# </objects>

配列.sum

[1,2,3,4,5,6,7,8,9,10].sum

配列.sum{|n| 条件}

[1,2,3,4,5,6,7,8,9,10].sum{|num| num %2 == 0}

duplicable?

"hoge".duplicable?
# true

"".duplicable?
# true

method(:puts).unbind.duplicable?
# false

Hash.from_trusted_xml(xml)

Hash.from_trusted_xml(xml)
# {"hash"=>{"foo"=>1, "bar"=>2}}

Hash.from_xml(xml)

Hash.from_xml(xml)
# {"hash"=>{"foo"=>1, "bar"=>2}}

ハッシュ.assert_valid_keys(キー名, ...)

{ name: 'Rob', years: '28' }.assert_valid_keys(:name, :age)
# raises "ArgumentError: Unknown key: :years. Valid keys are: :name, :age"

{ name: 'Rob', age: '28' }.assert_valid_keys('name', 'age')
# raises "ArgumentError: Unknown key: :name. Valid keys are: 'name', 'age'"

{ name: 'Rob', age: '28' }.assert_valid_keys(:name, :age)
# passes, raises nothing

ハッシュ.deep_dup

hash = { a: { b: 'b' } }
dup  = hash.deep_dup
dup[:a][:c] = 'c'
hash[:a][:c] # nil
dup[:a][:c]  # "c"

ハッシュ.deep_merge(ハッシュ)

h1 = { a: true, b: { c: [1, 2, 3] } }
h2 = { a: false, b: { x: [3, 4, 5] } }
h1.deep_merge(h2)
# { a: false, b: { c: [1, 2, 3], x: [3, 4, 5] } }

ハッシュ.deep_merge!(ハッシュ)

h1 = { a: true, b: { c: [1, 2, 3] } }
h2 = { a: false, b: { x: [3, 4, 5] } }
h1.deep_merge!(h2)
# { a: false, b: { c: [1, 2, 3], x: [3, 4, 5] } }

ハッシュ.deep_stringify_keys

hash = { person: { name: 'Rob', age: '28' } }
hash.deep_stringify_keys
# {"person"=>{"name"=>"Rob", "age"=>"28"}}

ハッシュ.deep_stringify_keys!

hash = { person: { name: 'Rob', age: '28' } }
hash.deep_stringify_keys!
# {"person"=>{"name"=>"Rob", "age"=>"28"}}

ハッシュ.deep_symbolize_keys

hash = {person: {name: 'Rob', age: '28'}}
hash.deep_symbolize_keys
# {:person=>{:name=>"Rob", :age=>"28"}}

ハッシュ.deep_symbolize_keys!

hash = {person: {name: 'Rob', age: '28'}}
hash.deep_symbolize_keys!
# {:person=>{:name=>"Rob", :age=>"28"}}

ハッシュ.deep_transform_keys{|key| 処理 }

hash = { person: { name: 'Rob', age: '28' } }
hash.deep_transform_keys{ |key| key.to_s.upcase }
# {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}

ハッシュ.deep_transform_keys!{|key| 処理 }

hash = { person: { name: 'Rob', age: '28' } }
hash.deep_transform_keys!{ |key| key.to_s.upcase }
# {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}

ハッシュ.deep_transform_values{|key| 処理 }

hash = { person: { name: 'Rob', age: '28' } }
hash.deep_transform_values{ |value| value.to_s.upcase }
# {person: {name: "ROB", age: "28"}}

ハッシュ.deep_transform_values!{|key| 処理 }

hash = { person: { name: 'Rob', age: '28' } }
hash.deep_transform_values!{ |value| value.to_s.upcase }
# {person: {name: "ROB", age: "28"}}

ハッシュ.except(キー名, ...)

{ a: true, b: false, c: nil }.except(:c)
# { a: true, b: false }

{ a: true, b: false, c: nil }.except(:a, :b)
# { c: nil }

ハッシュ.except!(キー名, ...)

{ a: true, b: false, c: nil }.except!(:c)
# { a: true, b: false }

{ a: true, b: false, c: nil }.except!(:a, :b)
# { c: nil }

ハッシュ.reverse_merge(ハッシュ)

options.reverse_merge(size: 25, velocity: 10)

ハッシュ.reverse_merge!(ハッシュ)

options.reverse_merge!(size: 25, velocity: 10)

ハッシュ.slice!(キー名)

hash = { a: 1, b: 2, c: 3, d: 4 }
hash.slice!(:a, :b)  # {:c=>3, :d=>4}
hash                 # {:a=>1, :b=>2}

ハッシュ.stringify_keys

hash = { name: 'Rob', age: '28' }
hash.stringify_keys
# {"name"=>"Rob", "age"=>"28"}

ハッシュ.stringify_keys!

hash = { name: 'Rob', age: '28' }
hash.stringify_keys!
# {"name"=>"Rob", "age"=>"28"}

ハッシュ.symbolize_keys

hash = {name: 'Rob', age: '28'}
hash.symbolize_keys
# {:name=>"Rob", :age=>"28"}

ハッシュ.symbolize_keys!

hash = {name: 'Rob', age: '28'}
hash.symbolize_keys!
# {:name=>"Rob", :age=>"28"}

ハッシュ.to_query([名前空間名]))

{name: 'David', nationality: 'Danish'}.to_query
# "name=David&nationality=Danish"

{name: 'David', nationality: 'Danish'}.to_query('user')
# "user%5Bname%5D=David&user%5Bnationality%5D=Danish"

ハッシュ.to_xml([オプション]))

{ foo: 1, bar: 2 }.to_xml
# <?xml version="1.0" encoding="UTF-8"?>
# <hash>
#   <foo type="integer">1</foo>
#   <bar type="integer">2</bar>
# </hash>

html_escape(文字列)

html_escape('is a > 0 & a < 10?')
# is a &gt; 0 &amp; a &lt; 10?

html_escape_once(文字列)

html_escape_once('<< Accept & Checkout')
# "<< Accept & Checkout"

数字.months

2.months
# 2 months

数字.multiple_of?(数字)

0.multiple_of?(0)
# true

6.multiple_of?(5)
# false

10.multiple_of?(2)
# true

数字.ordinal

1.ordinal
# "st"

2.ordinal
# "nd"

1002.ordinal
# "nd"

1003.ordinal
# "rd"

-11.ordinal
# "th"

-1001.ordinal
# "st"

数字.ordinalize

1.ordinalize
# "1st"

2.ordinalize
# "2nd"

1002.ordinalize
# "1002nd"

1003.ordinalize
# "1003rd"

-11.ordinalize
# "-11th"

-1001.ordinalize
# "-1001st"

数字.years

2.years
# 2 years

json_escape(文字列)

json_escape(json)
# "{\"name\":\"\\u003C/script\\u003E\\u003Cscript\\u003Ealert('PWNED!!!')\\u003C/script\\u003E\"}"

rescue_from(例外 , with: メソッド)

rescue_from User::NotAuthorized, with: :deny_access

Digest::UUID.uuid_v3(UUIDの名前空間, 名前)

Digest::UUID.uuid_v3("name_space", "sample")
# "3b0ead59-ca8d-350b-a392-e656db58b0fc"

Digest::UUID.uuid_v4

Digest::UUID.uuid_v4
# "4ad2a6a9-0135-4158-94d3-a33e41bbe048"

Digest::UUID.uuid_v5(UUIDの名前空間, 名前)

Digest::UUID.uuid_v5("name_space", "sample")
# "d7a9ae1a-b099-5318-8828-340cc10a1550"

オブジェクト.try(メソッド)

@person.try(:name)
# @person.name if @personと同じ

@person.try(:spouse).try(:name)

@person.try(:non_existing_method)x
# nil

オブジェクト.try(メソッド)

@person.try!(:name)

@person.try!(:spouse).try(:name)!

@person.try!(:non_existing_method)x
# nil

nil.try(:name) # => nil

@person&.name