Ruby on Rails ActiveSupport Core Extensions: String Inflection
Example
String#pluralize
Returns of plural form of the string. Optionally takes a count parameter and returns singular form if count == 1. Also accepts a locale parameter for language-specific pluralization.
'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" 'ley'.pluralize(1, :es) # => "ley"
String#singularize
Returns the singular form of the string. Accepts an optional locale parameter.
'posts'.singularize # => "post" 'octopi'.singularize # => "octopus" 'sheep'.singularize # => "sheep" 'word'.singularize # => "word" 'the blue mailmen'.singularize # => "the blue mailman" 'CamelOctopi'.singularize # => "CamelOctopus" 'leyes'.singularize(:es) # => "ley"
String#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.
'Module'.constantize # => Module 'Class'.constantize # => Class 'blargle'.constantize # => NameError: wrong constant name blargle
String#safe_constantize
Performs a constantize but returns nil instead of raising NameError.
'Module'.safe_constantize # => Module 'Class'.safe_constantize # => Class 'blargle'.safe_constantize # => nil
String#camelize
Converts strings to UpperCamelCase by default, if :lower is given as param converts to lowerCamelCase instead.
alias: camelcase
Note: will 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"
String#titleize
Capitalizes all the words and replaces some characters in the string to create a nicer looking title.
alias: titlecase
'man from the boondocks'.titleize # => "Man From The Boondocks" 'x-men: the last stand'.titleize # => "X Men: The Last Stand"
String#underscore
Makes an underscored, lowercase form from the expression in the string. The reverse of camelize.
Note: underscore will also change :: to / to convert namespaces to paths.
'ActiveModel'.underscore # => "active_model" 'ActiveModel::Errors'.underscore # => "active_model/errors"
String#dasherize
Replaces underscores with dashes in the string.
'puni_puni'.dasherize # => "puni-puni"
String#demodulize
Removes the module part from the constant expression in the string.
'ActiveRecord::CoreExtensions::String::Inflections'.demodulize # => "Inflections" 'Inflections'.demodulize # => "Inflections" '::Inflections'.demodulize # => "Inflections" ''.demodulize # => ''
String#deconstantize
Removes the rightmost segment from the constant expression in the string.
'Net::HTTP'.deconstantize # => "Net" '::Net::HTTP'.deconstantize # => "::Net" 'String'.deconstantize # => "" '::String'.deconstantize # => "" ''.deconstantize # => ""
String#parameterize
Replaces special characters in a string so that it may be used as part of a 'pretty' URL.
"Donald E. Knuth".parameterize # => "donald-e-knuth"
Preserve the case of the characters in a string with the :preserve_case argument.
"Donald E. Knuth".parameterize(preserve_case: true) # => "Donald-E-Knuth"
A very common use-case for parameterize is to override the to_param method of an ActiveRecord model to support more descriptive url slugs.
class Person < ActiveRecord::Base
def to_param
"#{id}-#{name.parameterize}"
end
end
Person.find(1).to_param # => "1-donald-e-knuth"
String#tableize
Creates the name of a table like Rails does for models to table names. Pluralizes the last word in the string.
'RawScaledScorer'.tableize # => "raw_scaled_scorers" 'ham_and_egg'.tableize # => "ham_and_eggs" 'fancyCategory'.tableize # => "fancy_categories"
String#classify
Returns a class name string from a plural table name like Rails does for table names to models.
'ham_and_eggs'.classify # => "HamAndEgg" 'posts'.classify # => "Post"
String#humanize
Capitalizes the first word, turns underscores into spaces, and strips a trailing _id if present.
'employee_salary'.humanize # => "Employee salary" 'author_id'.humanize # => "Author" 'author_id'.humanize(capitalize: false) # => "author" '_id'.humanize # => "Id"
String#upcase_first
Converts just the first character to uppercase.
'what a Lovely Day'.upcase_first # => "What a Lovely Day" 'w'.upcase_first # => "W" ''.upcase_first # => ""
String#foreign_key
Creates a foreign key name from a class name. Pass false param to disable adding _ between name and id.
'Message'.foreign_key # => "message_id" 'Message'.foreign_key(false) # => "messageid" 'Admin::Post'.foreign_key # => "post_id"
