Ruby on Rails latest stable (v5.2.3) - 5 notes - Class: Array
to_sentence(options = {}) public

Converts the array to a comma-separated sentence where the last element is joined by the connector word.

You can pass the following options to change the default behavior. If you pass an option key that doesn’t exist in the list below, it will raise an ArgumentError.


  • :words_connector - The sign or word used to join the elements in arrays with two or more elements (default: “, ”).

  • :two_words_connector - The sign or word used to join the elements in arrays with two elements (default: “ and ”).

  • :last_word_connector - The sign or word used to join the last element in arrays with three or more elements (default: “, and ”).

  • :locale - If i18n is available, you can set a locale and use the connector options defined on the ‘support.array’ namespace in the corresponding dictionary file.


[].to_sentence                      # => ""
['one'].to_sentence                 # => "one"
['one', 'two'].to_sentence          # => "one and two"
['one', 'two', 'three'].to_sentence # => "one, two, and three"

['one', 'two'].to_sentence(passing: 'invalid option')
# => ArgumentError: Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale

['one', 'two'].to_sentence(two_words_connector: '-')
# => "one-two"

['one', 'two', 'three'].to_sentence(words_connector: ' or ', last_word_connector: ' or at least ')
# => "one or two or at least three"

Using :locale option:

# Given this locale dictionary:
#   es:
#     support:
#       array:
#         words_connector: " o "
#         two_words_connector: " y "
#         last_word_connector: " o al menos "

['uno', 'dos'].to_sentence(locale: :es)
# => "uno y dos"

['uno', 'dos', 'tres'].to_sentence(locale: :es)
# => "uno o dos o al menos tres"
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December 17, 2011
2 thanks


[‘one’,‘two’,‘three’].to_sentence # => “one, two, and three”

April 1, 2014
2 thanks

Sometimes, you need the "Oxford comma"

Re: Gramatical error


We invited the strippers, JFK, and Stalin.

versus the appositive phrase:

We invited the strippers, JFK and Stalin.

(Really, you need to see the comic to appreciate the difference.)

April 1, 2014
0 thanks

Grammatical error

Hi - not sure where I would submit this so just putting here. My apologies if not in the right place.

default: “, and ” - this is grammatically wrong. There should be no comma with the last and.


[‘one’, ‘two’, ‘three’].to_sentence

should give: “one, two and three”

There is no ‘ .… , and ’ which is considered grammatically incorrect I feel. The ‘and’ does it’s job in the English language quite well by joining the two words it’s in between.

Thank you.

March 17, 2016
0 thanks

No grammatical error


“A, B, and C” is correct in English, and is preferred by most style manuals. “A, B and C” is also correct in English. See en.wikipedia.org/wiki/Serial_comma

May 28, 2019
0 thanks


By default, to_sentence combines elements inclusively by using ", and ".

If you want to be exclusive and combine the elements using ", or ", you can either pass in lengthy options to to_sentence or use this handy extension I made to add to_sentence_exclusive to the Array class.

class Array

  # Adds a simple method that overloads `to_sentence` except it uses "or" instead of "and", which is the default.
  # The reason for this is because `to_sentence` is extremely flexible but that results in a lot of code to get
  # the simple result of using "or" instead of "and". This makes it simple.
  def to_sentence_exclusive
    self.to_sentence( two_words_connector: " or ", last_word_connector: ", or " )


Just drop this in config/initializers/to_sentence_exclusive.rb, restart your server or console and Bob’s your uncle.