String inflections define new methods on the String class to transform names for different purposes. For instance, you can figure out the name of a database from the name of a class.
"ScaleScore".tableize # => "scale_scores"
Enable more predictable duck-typing on String-like classes. See Object#acts_like?.
# File lib/active_support/core_ext/string/behavior.rb, line 4 def acts_like_string? true end
# File lib/active_support/json/encoding.rb, line 172 def as_json(options = nil) self end
Returns the character at the position
treating the string as
an array (where 0 is the first character).
Examples:
"hello".at(0) # => "h" "hello".at(4) # => "o" "hello".at(10) # => ERROR if < 1.9, nil in 1.9
# File lib/active_support/core_ext/string/access.rb, line 11 def at(position) mb_chars[position, 1].to_s end
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.
"active_record".camelize # => "ActiveRecord" "active_record".camelize(:lower) # => "activeRecord" "active_record/errors".camelize # => "ActiveRecord::Errors" "active_record/errors".camelize(:lower) # => "activeRecord::Errors"
# File lib/active_support/core_ext/string/inflections.rb, line 55 def camelize(first_letter = :upper) case first_letter when :upper then ActiveSupport::Inflector.camelize(self, true) when :lower then ActiveSupport::Inflector.camelize(self, false) end end
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
.)
"egg_and_hams".classify # => "EggAndHam" "posts".classify # => "Post"
Singular names are not handled correctly.
"business".classify # => "Busines"
# File lib/active_support/core_ext/string/inflections.rb, line 140 def classify ActiveSupport::Inflector.classify(self) 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
# File lib/active_support/core_ext/string/inflections.rb, line 42 def constantize ActiveSupport::Inflector.constantize(self) end
Replaces underscores with dashes in the string.
"puni_puni" # => "puni-puni"
# File lib/active_support/core_ext/string/inflections.rb, line 89 def dasherize ActiveSupport::Inflector.dasherize(self) end
Removes the module part from the constant expression in the string.
"ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections" "Inflections".demodulize # => "Inflections"
# File lib/active_support/core_ext/string/inflections.rb, line 97 def demodulize ActiveSupport::Inflector.demodulize(self) end
# File lib/active_support/json/encoding.rb, line 173 def encode_json(encoder) encoder.escape(self) end
# File lib/active_support/core_ext/string/encoding.rb, line 3 def encoding_aware? true end
The inverse of String#include?. Returns true if the string does not include the other string.
# File lib/active_support/core_ext/string/exclude.rb, line 3 def exclude?(string) !include?(string) end
Returns the first character of the string or the first limit
characters.
Examples:
"hello".first # => "h" "hello".first(2) # => "he" "hello".first(10) # => "hello"
# File lib/active_support/core_ext/string/access.rb, line 41 def first(limit = 1) if limit == 0 '' elsif limit >= size self else mb_chars[0...limit].to_s end 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"
# File lib/active_support/core_ext/string/inflections.rb, line 161 def foreign_key(separate_class_name_and_id_with_underscore = true) ActiveSupport::Inflector.foreign_key(self, separate_class_name_and_id_with_underscore) end
Returns the remaining of the string from the position
treating
the string as an array (where 0 is the first character).
Examples:
"hello".from(0) # => "hello" "hello".from(2) # => "llo" "hello".from(10) # => "" if < 1.9, nil in 1.9
# File lib/active_support/core_ext/string/access.rb, line 21 def from(position) mb_chars[position..-1].to_s end
# File lib/active_support/core_ext/string/output_safety.rb, line 166 def html_safe ActiveSupport::SafeBuffer.new(self) end
Capitalizes the first word, turns underscores into spaces, and strips
'_id'. Like titleize
, this is meant for creating pretty
output.
"employee_salary" # => "Employee salary" "author_id" # => "Author"
# File lib/active_support/core_ext/string/inflections.rb, line 149 def humanize ActiveSupport::Inflector.humanize(self) end
Returns the last character of the string or the last limit
characters.
Examples:
"hello".last # => "o" "hello".last(2) # => "lo" "hello".last(10) # => "hello"
# File lib/active_support/core_ext/string/access.rb, line 57 def last(limit = 1) if limit == 0 '' elsif limit >= size self else mb_chars[(-limit)..-1].to_s end end
Replaces special characters in a string so that it may be used as part of a 'pretty' URL.
class Person def to_param "#{id}-#{name.parameterize}" end end @person = Person.find(1) # => #<Person id: 1, name: "Donald E. Knuth"> <%= link_to(@person.name, person_path %> # => <a href="/person/1-donald-e-knuth">Donald E. Knuth</a>
# File lib/active_support/core_ext/string/inflections.rb, line 116 def parameterize(sep = '-') ActiveSupport::Inflector.parameterize(self, sep) end
Returns the plural form of the word in the string.
"post".pluralize # => "posts" "octopus".pluralize # => "octopi" "sheep".pluralize # => "sheep" "words".pluralize # => "words" "the blue mailman".pluralize # => "the blue mailmen" "CamelOctopus".pluralize # => "CamelOctopi"
# File lib/active_support/core_ext/string/inflections.rb, line 19 def pluralize ActiveSupport::Inflector.pluralize(self) end
The reverse of pluralize
, returns the singular form of a word
in a string.
"posts".singularize # => "post" "octopi".singularize # => "octopus" "sheep".singularize # => "sheep" "word".singularize # => "word" "the blue mailmen".singularize # => "the blue mailman" "CamelOctopi".singularize # => "CamelOctopus"
# File lib/active_support/core_ext/string/inflections.rb, line 31 def singularize ActiveSupport::Inflector.singularize(self) end
Returns the string, first removing all whitespace on both ends of the string, and then changing remaining consecutive whitespace groups into one space each.
Examples:
%Q{ Multi-line string }.squish # => "Multi-line string" " foo bar \n \t boo".squish # => "foo bar boo"
# File lib/active_support/core_ext/string/filters.rb, line 12 def squish dup.squish! end
Performs a destructive squish. See #squish.
# File lib/active_support/core_ext/string/filters.rb, line 17 def squish! strip! gsub!(%r\s+/, ' ') self end
Strips indentation in heredocs.
For example in
if options[:usage] puts <<-USAGE.strip_heredoc This command does such and such. Supported options are: -h This message ... USAGE end
the user would see the usage message aligned against the left margin.
Technically, it looks for the least indented line in the whole string, and removes that amount of leading whitespace.
# File lib/active_support/core_ext/string/strip.rb, line 22 def strip_heredoc indent = scan(%r^[ \t]*(?=\S)/).min.try(:size) || 0 gsub(%r^[ \t]{#{indent}}/, '') end
Creates 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.
"RawScaledScorer".tableize # => "raw_scaled_scorers" "egg_and_ham".tableize # => "egg_and_hams" "fancyCategory".tableize # => "fancy_categories"
# File lib/active_support/core_ext/string/inflections.rb, line 126 def tableize ActiveSupport::Inflector.tableize(self) 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 titlecase
.
"man from the boondocks".titleize # => "Man From The Boondocks" "x-men: the last stand".titleize # => "X Men: The Last Stand"
# File lib/active_support/core_ext/string/inflections.rb, line 71 def titleize ActiveSupport::Inflector.titleize(self) end
Returns the beginning of the string up to the position
treating the string as an array (where 0 is the first character).
Examples:
"hello".to(0) # => "h" "hello".to(2) # => "hel" "hello".to(10) # => "hello"
# File lib/active_support/core_ext/string/access.rb, line 31 def to(position) mb_chars[0..position].to_s end
Truncates a given text
after a given length
if
text
is longer than length
:
"Once upon a time in a world far far away".truncate(27) # => "Once upon a time in a wo..."
The last characters will be replaced with the :omission
string
(defaults to "...") for a total length not exceeding :length
:
"Once upon a time in a world far far away".truncate(27, :separator => ' ') # => "Once upon a time in a..."
Pass a :separator
to truncate text
at a natural
break:
"And they found that many people were sleeping better.".truncate(25, :omission => "... (continued)") # => "And they f... (continued)"
# File lib/active_support/core_ext/string/filters.rb, line 38 def truncate(length, options = {}) text = self.dup options[:omission] ||= "..." length_with_room_for_omission = length - options[:omission].mb_chars.length chars = text.mb_chars stop = options[:separator] ? (chars.rindex(options[:separator].mb_chars, length_with_room_for_omission) || length_with_room_for_omission) : length_with_room_for_omission (chars.length > length ? chars[0...stop] + options[:omission] : text).to_s end
The reverse of camelize
. Makes an underscored, lowercase form
from the expression in the string.
underscore
will also change '::' to '/' to convert namespaces
to paths.
"ActiveRecord".underscore # => "active_record" "ActiveRecord::Errors".underscore # => active_record/errors
# File lib/active_support/core_ext/string/inflections.rb, line 82 def underscore ActiveSupport::Inflector.underscore(self) end