Ruby-单词数组中类似英语的句子列表

Question

Is there a Ruby/Rails "magic" helper to go from an array of words, like

["Sugar", "Water", "Lemons", "Tea"]

to a single string which can fit in a sentence:

"Sugar, Water, Lemons and Tea"

I know about array.join() , but the "and" before the last entry is important.
I am just asking because I know Ruby and Rails have a lot of helpful methods lurking in the dark and I want to keep my code as clean as possible

Answer 1

Seems like this is what you're looking for :)

http://apidock.com/rails/Array/to_sentence

to_sentence(options = {})

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

Example:

["Sugar", "Water", "Lemons", "Tea"].to_sentence # => "Sugar, Water, Lemons, and Tea"

You can also pass options, like what should be your last word connector:

["Sugar", "Water", "Lemons", "Tea"].to_sentence(last_word_connector: ' or ') # => "Sugar, Water, Lemons or Tea"

EDIT:

As pointed out by Max Williams, this will by default leave a comma next to the last word. To avoid that, you can explicitly declare " and " as your last word connector, as the default seems to be ", and "

["Sugar", "Water", "Lemons", "Tea"].to_sentence(last_word_connector: ' and ') # => "Sugar, Water, Lemons and Tea"

Answer 2

try this

pry(main)> ["Sugar", "Water", "Lemons", "Tea"].to_sentence
=> "Sugar, Water, Lemons, and Tea"

or

 pry(main)> ["Sugar", "Water", "Lemons", "Tea"].to_sentence(words_connector: ', ', last_word_connector: ' and ')
  => "Sugar, Water, Lemons and Tea"

Answer 3

You can still use join, just do the last element separately.

def commas_with_and(arr)
  arr[0..-2].join(", ") << " and " << arr[-1]
end

arr = ["Sugar", "Water", "Lemons", "Tea"]
commas_with_and(arr)
>>  "Sugar, Water, Lemons and Tea"