Module: ActiveSupport::Inflector

Extended by:
Inflector
Included in:
Inflector
Defined in:
activesupport/lib/active_support/inflector.rb

Overview

The Inflector transforms words from singular to plural, class names to table names, modularized class names to ones without, and class names to foreign keys. The default inflections for pluralization, singularization, and uncountable words are kept in inflections.rb.

The Rails core team has stated patches for the inflections library will not be accepted in order to avoid breaking legacy applications which may be relying on errant inflections. If you discover an incorrect inflection and require it for your application, you'll need to correct it yourself (explained below).

Defined Under Namespace

Classes: Inflections

Instance Method Summary (collapse)

Instance Method Details

- (Object) camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)

By default, camelize converts strings to UpperCamelCase. If the argument to camelize is set to :lower then camelize produces lowerCamelCase.

camelize will also convert '/' to '::' which is useful for converting paths to namespaces.

Examples:

"active_record".camelize                # => "ActiveRecord"
"active_record".camelize(:lower)        # => "activeRecord"
"active_record/errors".camelize         # => "ActiveRecord::Errors"
"active_record/errors".camelize(:lower) # => "activeRecord::Errors"


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# File 'activesupport/lib/active_support/inflector.rb', line 179

def camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)
  if first_letter_in_uppercase
    lower_case_and_underscored_word.to_s.gsub(/\/(.?)/) { "::#{$1.upcase}" }.gsub(/(?:^|_)(.)/) { $1.upcase }
  else
    lower_case_and_underscored_word.first.downcase + camelize(lower_case_and_underscored_word)[1..-1]
  end
end

- (Object) classify(table_name)

Create a class name from a plural table name like Rails does for table names to models. Note that this returns a string and not a Class. (To convert to an actual class follow classify with constantize.)

Examples:

"egg_and_hams".classify # => "EggAndHam"
"posts".classify        # => "Post"

Singular names are not handled correctly:

"business".classify     # => "Busines"


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# File 'activesupport/lib/active_support/inflector.rb', line 321

def classify(table_name)
  # strip out any leading schema name
  camelize(singularize(table_name.to_s.sub(/.*\./, '')))
end

- (Object) constantize(camel_cased_word)



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# File 'activesupport/lib/active_support/inflector.rb', line 358

def constantize(camel_cased_word)
  names = camel_cased_word.split('::')
  names.shift if names.empty? || names.first.empty?

  constant = Object
  names.each do |name|
    constant = constant.const_defined?(name) ? constant.const_get(name) : constant.const_missing(name)
  end
  constant
end

- (Object) dasherize(underscored_word)

Replaces underscores with dashes in the string.

Example:

"puni_puni" # => "puni-puni"


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# File 'activesupport/lib/active_support/inflector.rb', line 219

def dasherize(underscored_word)
  underscored_word.gsub(/_/, '-')
end

- (Object) demodulize(class_name_in_module)

Removes the module part from the expression in the string.

Examples:

"ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
"Inflections".demodulize                                       # => "Inflections"


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# File 'activesupport/lib/active_support/inflector.rb', line 241

def demodulize(class_name_in_module)
  class_name_in_module.to_s.gsub(/^.*::/, '')
end

- (Object) foreign_key(class_name, separate_class_name_and_id_with_underscore = true)

Creates a foreign key name from a class name. separate_class_name_and_id_with_underscore sets whether the method should put '_' between the name and 'id'.

Examples:

"Message".foreign_key        # => "message_id"
"Message".foreign_key(false) # => "messageid"
"Admin::Post".foreign_key    # => "post_id"


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# File 'activesupport/lib/active_support/inflector.rb', line 334

def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
  underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id")
end

- (Object) humanize(lower_case_and_underscored_word)

Capitalizes the first word and turns underscores into spaces and strips a trailing “_id”, if any. Like titleize, this is meant for creating pretty output.

Examples:

"employee_salary" # => "Employee salary"
"author_id"       # => "Author"


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# File 'activesupport/lib/active_support/inflector.rb', line 229

def humanize(lower_case_and_underscored_word)
  result = lower_case_and_underscored_word.to_s.dup

  inflections.humans.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
  result.gsub(/_id$/, "").gsub(/_/, " ").capitalize
end

- (Object) inflections

Yields a singleton instance of Inflector::Inflections so you can specify additional inflector rules.

Example:

ActiveSupport::Inflector.inflections do |inflect|
  inflect.uncountable "rails"
end


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# File 'activesupport/lib/active_support/inflector.rb', line 123

def inflections
  if block_given?
    yield Inflections.instance
  else
    Inflections.instance
  end
end

- (Object) ordinalize(number)

Turns a number into an ordinal string used to denote the position in an ordered sequence such as 1st, 2nd, 3rd, 4th.

Examples:

ordinalize(1)     # => "1st"
ordinalize(2)     # => "2nd"
ordinalize(1002)  # => "1002nd"
ordinalize(1003)  # => "1003rd"


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# File 'activesupport/lib/active_support/inflector.rb', line 389

def ordinalize(number)
  if (11..13).include?(number.to_i % 100)
    "#{number}th"
  else
    case number.to_i % 10
      when 1; "#{number}st"
      when 2; "#{number}nd"
      when 3; "#{number}rd"
      else    "#{number}th"
    end
  end
end

- (Object) parameterize(string, sep = '-')

Replaces special characters in a string so that it may be used as part of a 'pretty' URL.

Examples

class Person
  def to_param
    "#{id}-#{name.parameterize}"
  end
end

@person = Person.find(1)
# => #<Person id: 1, name: "Donald E. Knuth">

<%= link_to(@person.name, person_path(@person)) %>
# => <a href="/person/1-donald-e-knuth">Donald E. Knuth</a>


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# File 'activesupport/lib/active_support/inflector.rb', line 260

def parameterize(string, sep = '-')
  # remove malformed utf8 characters
  string = string.toutf8 unless string.is_utf8?
  # replace accented chars with ther ascii equivalents
  parameterized_string = transliterate(string)
  # Turn unwanted chars into the seperator
  parameterized_string.gsub!(/[^a-z0-9\-_]+/i, sep)
  unless sep.blank?
    re_sep = Regexp.escape(sep)
    # No more than one of the separator in a row.
    parameterized_string.gsub!(/#{re_sep}{2,}/, sep)
    # Remove leading/trailing separator.
    parameterized_string.gsub!(/^#{re_sep}|#{re_sep}$/i, '')
  end
  parameterized_string.downcase
end

- (Object) pluralize(word)

Returns the plural form of the word in the string.

Examples:

"post".pluralize             # => "posts"
"octopus".pluralize          # => "octopi"
"sheep".pluralize            # => "sheep"
"words".pluralize            # => "words"
"CamelOctopus".pluralize     # => "CamelOctopi"


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# File 'activesupport/lib/active_support/inflector.rb', line 139

def pluralize(word)
  result = word.to_s.dup

  if word.empty? || inflections.uncountables.include?(result.downcase)
    result
  else
    inflections.plurals.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
    result
  end
end

- (Object) singularize(word)

The reverse of pluralize, returns the singular form of a word in a string.

Examples:

"posts".singularize            # => "post"
"octopi".singularize           # => "octopus"
"sheep".singluarize            # => "sheep"
"word".singularize             # => "word"
"CamelOctopi".singularize      # => "CamelOctopus"


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# File 'activesupport/lib/active_support/inflector.rb', line 158

def singularize(word)
  result = word.to_s.dup

  if inflections.uncountables.any? { |inflection| result =~ /#{inflection}\Z/i }
    result
  else
    inflections.singulars.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
    result
  end
end

- (Object) tableize(class_name)

Create the name of a table like Rails does for models to table names. This method uses the pluralize method on the last word in the string.

Examples

"RawScaledScorer".tableize # => "raw_scaled_scorers"
"egg_and_ham".tableize     # => "egg_and_hams"
"fancyCategory".tableize   # => "fancy_categories"


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# File 'activesupport/lib/active_support/inflector.rb', line 307

def tableize(class_name)
  pluralize(underscore(class_name))
end

- (Object) titleize(word)

Capitalizes all the words and replaces some characters in the string to create a nicer looking title. titleize is meant for creating pretty output. It is not used in the Rails internals.

titleize is also aliased as as titlecase.

Examples:

"man from the boondocks".titleize # => "Man From The Boondocks"
"x-men: the last stand".titleize  # => "X Men: The Last Stand"


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# File 'activesupport/lib/active_support/inflector.rb', line 196

def titleize(word)
  humanize(underscore(word)).gsub(/\b('?[a-z])/) { $1.capitalize }
end

- (Object) transliterate(string)

Replaces accented characters with their ascii equivalents.



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# File 'activesupport/lib/active_support/inflector.rb', line 279

def transliterate(string)
  Iconv.iconv('ascii//ignore//translit', 'utf-8', string).to_s
end

- (Object) underscore(camel_cased_word)

The reverse of camelize. Makes an underscored, lowercase form from the expression in the string.

Changes '::' to '/' to convert namespaces to paths.

Examples:

"ActiveRecord".underscore         # => "active_record"
"ActiveRecord::Errors".underscore # => active_record/errors


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# File 'activesupport/lib/active_support/inflector.rb', line 207

def underscore(camel_cased_word)
  camel_cased_word.to_s.gsub(/::/, '/').
    gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(/([a-z\d])([A-Z])/,'\1_\2').
    tr("-", "_").
    downcase
end