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camelize and underscore are sort of inverse of each other, but not in…

… a mathematical sense [#5174 state:resolved]
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1 parent b72cc47 commit b456877cfb7e0cb0bab9ffd5674abd23caba0ab4 @fxn fxn committed Jul 21, 2010
@@ -20,6 +20,11 @@ module Inflector
# "active_record".camelize(:lower) # => "activeRecord"
# "active_record/errors".camelize # => "ActiveRecord::Errors"
# "active_record/errors".camelize(:lower) # => "activeRecord::Errors"
+ #
+ # As a rule of thumb you can think of +camelize+ as the inverse of +underscore+,
+ # though there are cases where that does not hold:
+ #
+ # "SSLError".underscore.camelize # => "SslError"
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 }
@@ -28,13 +33,18 @@ def camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)
end
end
- # The reverse of +camelize+. Makes an underscored, lowercase form from the expression in the string.
+ # 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
+ #
+ # As a rule of thumb you can think of +underscore+ as the inverse of +camelize+,
+ # though there are cases where that does not hold:
+ #
+ # "SSLError".underscore.camelize # => "SslError"
def underscore(camel_cased_word)
word = camel_cased_word.to_s.dup
word.gsub!(/::/, '/')
@@ -1491,13 +1491,15 @@ end
That may be handy to compute method names in a language that follows that convention, for example JavaScript.
+INFO: As a rule of thumb you can think of +camelize+ as the inverse of +underscore+, though there are cases where that does not hold: <tt>"SSLError".underscore.camelize</tt> gives back <tt>"SslError"</tt>.
+
+camelize+ is aliased to +camelcase+.
NOTE: Defined in +active_support/core_ext/string/inflections.rb+.
h5. +underscore+
-The method +underscore+ is the inverse of +camelize+, explained above:
+The method +underscore+ goes the other way around, from camel case to paths:
<ruby>
"Product".underscore # => "product"
@@ -1530,6 +1532,8 @@ def load_missing_constant(from_mod, const_name)
end
</ruby>
+INFO: As a rule of thumb you can think of +underscore+ as the inverse of +camelize+, though there are cases where that does not hold. For example, <tt>"SSLError".underscore.camelize</tt> gives back <tt>"SslError"</tt>.
+
NOTE: Defined in +active_support/core_ext/string/inflections.rb+.
h5. +titleize+

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