instance method `underscore`

Ruby on Rails 6.0.6

Since v2.2.3

Available in: v2.2.3 v2.3.18 v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

underscore(camel_cased_word)

Makes an underscored, lowercase form from the expression in the string.

Changes ‘::’ to ‘/’ to convert namespaces to paths.

underscore('ActiveModel')         # => "active_model"
underscore('ActiveModel::Errors') # => "active_model/errors"

As a rule of thumb you can think of underscore as the inverse of #camelize, though there are cases where that does not hold:

camelize(underscore('SSLError'))  # => "SslError"

Parameters

camel_cased_word req

Source

# File activesupport/lib/active_support/inflector/methods.rb, line 91
    def underscore(camel_cased_word)
      return camel_cased_word unless /[A-Z-]|::/.match?(camel_cased_word)
      word = camel_cased_word.to_s.gsub("::", "/")
      word.gsub!(inflections.acronyms_underscore_regex) { "#{$1 && '_' }#{$2.downcase}" }
      word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2')
      word.gsub!(/([a-z\d])([A-Z])/, '\1_\2')
      word.tr!("-", "_")
      word.downcase!
      word
    end

Defined in activesupport/lib/active_support/inflector/methods.rb line 91 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveSupport::Inflector

Signature

Parameters