Module: Inflector
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
-
#camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true) ⇒ Object
By default,
camelize
converts strings to UpperCamelCase. -
#classify(table_name) ⇒ Object
Create a class name from a plural table name like Rails does for table names to models.
-
#constantize(camel_cased_word) ⇒ Object
Tries to find a constant with the name specified in the argument string:.
-
#dasherize(underscored_word) ⇒ Object
Replaces underscores with dashes in the string.
-
#demodulize(class_name_in_module) ⇒ Object
Removes the module part from the expression in the string.
-
#foreign_key(class_name, separate_class_name_and_id_with_underscore = true) ⇒ Object
Creates a foreign key name from a class name.
-
#humanize(lower_case_and_underscored_word) ⇒ Object
Capitalizes the first word and turns underscores into spaces and strips a trailing “_id”, if any.
-
#inflections ⇒ Object
Yields a singleton instance of Inflector::Inflections so you can specify additional inflector rules.
-
#ordinalize(number) ⇒ Object
Turns a number into an ordinal string used to denote the position in an ordered sequence such as 1st, 2nd, 3rd, 4th.
-
#pluralize(word) ⇒ Object
Returns the plural form of the word in the string.
-
#singularize(word) ⇒ Object
The reverse of
pluralize
, returns the singular form of a word in a string. -
#tableize(class_name) ⇒ Object
Create the name of a table like Rails does for models to table names.
-
#titleize(word) ⇒ Object
Capitalizes all the words and replaces some characters in the string to create a nicer looking title.
-
#underscore(camel_cased_word) ⇒ Object
The reverse of
camelize
.
Instance Method Details
#camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true) ⇒ Object
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 'lib/active_support/inflector.rb', line 160 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 + camelize(lower_case_and_underscored_word)[1..-1] end end |
#classify(table_name) ⇒ Object
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 'lib/active_support/inflector.rb', line 244 def classify(table_name) # strip out any leading schema name camelize(singularize(table_name.to_s.sub(/.*\./, ''))) end |
#constantize(camel_cased_word) ⇒ Object
Tries to find a constant with the name specified in the argument string:
"Module".constantize # => Module
"Test::Unit".constantize # => Test::Unit
The name is assumed to be the one of a top-level constant, no matter whether it starts with “::” or not. No lexical context is taken into account:
C = 'outside'
module M
C = 'inside'
C # => 'inside'
"C".constantize # => 'outside', same as ::C
end
NameError is raised when the name is not in CamelCase or the constant is unknown.
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# File 'lib/active_support/inflector.rb', line 278 def constantize(camel_cased_word) unless /\A(?:::)?([A-Z]\w*(?:::[A-Z]\w*)*)\z/ =~ camel_cased_word raise NameError, "#{camel_cased_word.inspect} is not a valid constant name!" end Object.module_eval("::#{$1}", __FILE__, __LINE__) end |
#dasherize(underscored_word) ⇒ Object
Replaces underscores with dashes in the string.
Example:
"puni_puni" # => "puni-puni"
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# File 'lib/active_support/inflector.rb', line 200 def dasherize(underscored_word) underscored_word.gsub(/_/, '-') end |
#demodulize(class_name_in_module) ⇒ Object
Removes the module part from the expression in the string.
Examples:
"ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
"Inflections".demodulize # => "Inflections"
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# File 'lib/active_support/inflector.rb', line 219 def demodulize(class_name_in_module) class_name_in_module.to_s.gsub(/^.*::/, '') end |
#foreign_key(class_name, separate_class_name_and_id_with_underscore = true) ⇒ Object
Creates a foreign key name from a class name. separate_class_name_and_id_with_underscore
sets whether the method should put ‘_’ between the name and ‘id’.
Examples:
"Message".foreign_key # => "message_id"
"Message".foreign_key(false) # => "messageid"
"Admin::Post".foreign_key # => "post_id"
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# File 'lib/active_support/inflector.rb', line 257 def foreign_key(class_name, separate_class_name_and_id_with_underscore = true) underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id") end |
#humanize(lower_case_and_underscored_word) ⇒ Object
Capitalizes the first word and turns underscores into spaces and strips a trailing “_id”, if any. Like titleize
, this is meant for creating pretty output.
Examples:
"employee_salary" # => "Employee salary"
"author_id" # => "Author"
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# File 'lib/active_support/inflector.rb', line 210 def humanize(lower_case_and_underscored_word) lower_case_and_underscored_word.to_s.gsub(/_id$/, "").gsub(/_/, " ").capitalize end |
#inflections ⇒ Object
Yields a singleton instance of Inflector::Inflections so you can specify additional inflector rules.
Example:
Inflector.inflections do |inflect|
inflect.uncountable "rails"
end
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# File 'lib/active_support/inflector.rb', line 102 def inflections if block_given? yield Inflections.instance else Inflections.instance end end |
#ordinalize(number) ⇒ Object
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 'lib/active_support/inflector.rb', line 294 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 |
#pluralize(word) ⇒ Object
Returns the plural form of the word in the string.
Examples:
"post".pluralize # => "posts"
"octopus".pluralize # => "octopi"
"sheep".pluralize # => "sheep"
"words".pluralize # => "words"
"the blue mailman".pluralize # => "the blue mailmen"
"CamelOctopus".pluralize # => "CamelOctopi"
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# File 'lib/active_support/inflector.rb', line 119 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 |
#singularize(word) ⇒ Object
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".singluarize # => "word"
"the blue mailmen".singularize # => "the blue mailman"
"CamelOctopi".singularize # => "CamelOctopus"
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# File 'lib/active_support/inflector.rb', line 139 def singularize(word) result = word.to_s.dup if inflections.uncountables.include?(result.downcase) result else inflections.singulars.each { |(rule, replacement)| break if result.gsub!(rule, replacement) } result end end |
#tableize(class_name) ⇒ Object
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 'lib/active_support/inflector.rb', line 230 def tableize(class_name) pluralize(underscore(class_name)) end |
#titleize(word) ⇒ Object
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 'lib/active_support/inflector.rb', line 177 def titleize(word) humanize(underscore(word)).gsub(/\b('?[a-z])/) { $1.capitalize } end |
#underscore(camel_cased_word) ⇒ Object
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 'lib/active_support/inflector.rb', line 188 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 |