String inflections define new methods on the String class to transform names for different purposes. For instance, you can figure out the name of a database from the name of a class.

"ScaleScore".tableize # => "scale_scores"
Methods
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Instance Public methods
camelcase(first_letter = :upper)
camelize(first_letter = :upper)

By default, camelizeconverts strings to UpperCamelCase. If the argument to camelize is set to :lowerthen camelize produces lowerCamelCase.

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

"active_record".camelize                # => "ActiveRecord"
"active_record".camelize(:lower)        # => "activeRecord"
"active_record/errors".camelize         # => "ActiveRecord::Errors"
"active_record/errors".camelize(:lower) # => "activeRecord::Errors"
Also aliased as: camelcase
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 44
def camelize(first_letter = :upper)
  case first_letter
    when :upper then Inflector.camelize(self, true)
    when :lower then Inflector.camelize(self, false)
  end
end
classify()

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 classifywith constantize.)

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

Singular names are not handled correctly.

"business".classify # => "Busines"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 129
def classify
  Inflector.classify(self)
end
constantize()

constantizetries to find a declared constant with the name specified in the string. It raises a NameError when the name is not in CamelCase or is not initialized.

Examples

"Module".constantize # => Module
"Class".constantize  # => Class
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 161
def constantize
  Inflector.constantize(self)
end
dasherize()

Replaces underscores with dashes in the string.

"puni_puni" # => "puni-puni"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 78
def dasherize
  Inflector.dasherize(self)
end
demodulize()

Removes the module part from the constant expression in the string.

"ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
"Inflections".demodulize                                       # => "Inflections"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 86
def demodulize
  Inflector.demodulize(self)
end
foreign_key(separate_class_name_and_id_with_underscore = true)

Creates a foreign key name from a class name. separate_class_name_and_id_with_underscoresets 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"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 150
def foreign_key(separate_class_name_and_id_with_underscore = true)
  Inflector.foreign_key(self, separate_class_name_and_id_with_underscore)
end
humanize()

Capitalizes the first word, turns underscores into spaces, and strips '_id'. Like titleize, this is meant for creating pretty output.

"employee_salary" # => "Employee salary" 
"author_id"       # => "Author"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 138
def humanize
  Inflector.humanize(self)
end
parameterize(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 %>
# => <a href="/person/1-donald-e-knuth">Donald E. Knuth</a>
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 105
def parameterize(sep = '-')
  Inflector.parameterize(self, sep)
end
pluralize()

Returns the plural form of the word in the string.

"post".pluralize             # => "posts"
"octopus".pluralize          # => "octopi"
"sheep".pluralize            # => "sheep"
"words".pluralize            # => "words"
"the blue mailman".pluralize # => "the blue mailmen"
"CamelOctopus".pluralize     # => "CamelOctopi"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 19
def pluralize
  Inflector.pluralize(self)
end
singularize()

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

"posts".singularize            # => "post"
"octopi".singularize           # => "octopus"
"sheep".singularize            # => "sheep"
"word".singularize             # => "word"
"the blue mailmen".singularize # => "the blue mailman"
"CamelOctopi".singularize      # => "CamelOctopus"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 31
def singularize
  Inflector.singularize(self)
end
tableize()

Creates 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.

"RawScaledScorer".tableize # => "raw_scaled_scorers"
"egg_and_ham".tableize     # => "egg_and_hams"
"fancyCategory".tableize   # => "fancy_categories"
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 115
def tableize
  Inflector.tableize(self)
end
titlecase()
titleize()

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

titleizeis also aliased as titlecase.

"man from the boondocks".titleize # => "Man From The Boondocks"
"x-men: the last stand".titleize  # => "X Men: The Last Stand"
Also aliased as: titlecase
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 60
def titleize
  Inflector.titleize(self)
end
underscore()

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

underscorewill also change '::' to '/' to convert namespaces to paths.

"ActiveRecord".underscore         # => "active_record"
"ActiveRecord::Errors".underscore # => active_record/errors
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 71
def underscore
  Inflector.underscore(self)
end