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.
- camelize
- classify
- constantize
- dasherize
- demodulize
- foreign_key
- humanize
- inflections
- ordinalize
- pluralize
- singularize
- tableize
- titleize
- underscore
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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 140
140: def camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)
141: if first_letter_in_uppercase
142: lower_case_and_underscored_word.to_s.gsub(/\/(.?)/) { "::" + $1.upcase }.gsub(/(^|_)(.)/) { $2.upcase }
143: else
144: lower_case_and_underscored_word.first + camelize(lower_case_and_underscored_word)[1..-1]
145: end
146: end
Create a class name from a 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" "post".classify #=> "Post"
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 221
221: def classify(table_name)
222: # strip out any leading schema name
223: camelize(singularize(table_name.to_s.sub(/.*\./, '')))
224: end
Constantize tries 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
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 245
245: def constantize(camel_cased_word)
246: unless /\A(?:::)?([A-Z]\w*(?:::[A-Z]\w*)*)\z/ =~ camel_cased_word
247: raise NameError, "#{camel_cased_word.inspect} is not a valid constant name!"
248: end
249:
250: Object.module_eval("::#{$1}", __FILE__, __LINE__)
251: end
Replaces underscores with dashes in the string.
Example
"puni_puni" #=> "puni-puni"
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 180
180: def dasherize(underscored_word)
181: underscored_word.gsub(/_/, '-')
182: end
Removes the module part from the expression in the string
Examples
"ActiveRecord::CoreExtensions::String::Inflections".demodulize #=> "Inflections" "Inflections".demodulize #=> "Inflections"
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 199
199: def demodulize(class_name_in_module)
200: class_name_in_module.to_s.gsub(/^.*::/, '')
201: end
Creates a foreign key name from a class name. separate_class_name_and_id_with_underscore sets whether the method should put ‘_’ between the name and ‘id’.
Examples
"Message".foreign_key #=> "message_id" "Message".foreign_key(false) #=> "messageid" "Admin::Post".foreign_key #=> "post_id"
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 234
234: def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
235: underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id")
236: end
Capitalizes the first word and turns underscores into spaces and strips _id. Like titleize, this is meant for creating pretty output.
Examples
"employee_salary" #=> "Employee salary" "author_id" #=> "Author"
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 190
190: def humanize(lower_case_and_underscored_word)
191: lower_case_and_underscored_word.to_s.gsub(/_id$/, "").gsub(/_/, " ").capitalize
192: end
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# File vendor/rails/activesupport/lib/active_support/inflector.rb, line 82
82: def inflections
83: if block_given?
84: yield Inflections.instance
85: else
86: Inflections.instance
87: end
88: end
Ordinalize 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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 261
261: def ordinalize(number)
262: if (11..13).include?(number.to_i % 100)
263: "#{number}th"
264: else
265: case number.to_i % 10
266: when 1: "#{number}st"
267: when 2: "#{number}nd"
268: when 3: "#{number}rd"
269: else "#{number}th"
270: end
271: end
272: end
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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 99
99: def pluralize(word)
100: result = word.to_s.dup
101:
102: if inflections.uncountables.include?(result.downcase)
103: result
104: else
105: inflections.plurals.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
106: result
107: end
108: end
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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 119
119: def singularize(word)
120: result = word.to_s.dup
121:
122: if inflections.uncountables.include?(result.downcase)
123: result
124: else
125: inflections.singulars.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
126: result
127: end
128: end
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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 210
210: def tableize(class_name)
211: pluralize(underscore(class_name))
212: end
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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 157
157: def titleize(word)
158: humanize(underscore(word)).gsub(/\b([a-z])/) { $1.capitalize }
159: end
The reverse of camelize. Makes an underscored 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 vendor/rails/activesupport/lib/active_support/inflector.rb, line 168
168: def underscore(camel_cased_word)
169: camel_cased_word.to_s.gsub(/::/, '/').
170: gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
171: gsub(/([a-z\d])([A-Z])/,'\1_\2').
172: tr("-", "_").
173: downcase
174: end