Most frequently used word codewars challenge https://www.codewars.com/kata/most-frequently-used-words-in-a-text/ruby

frequently_used.rb

def top_3_words(text)
  sterilized_words(text).reduce({}, &count_words)
  .sort_by(&by_count).map(&first).reverse.take(3)
end

def count_words
  lambda do |result, word| 
    result[word] = (result[word] || 0) + 1 ; 
    result 
  end
end

def by_count
  -> _word, count { count }
end

def first
  -> pair { pair[0] }
end

def sterilized_words(text)
  text.gsub("\n", " ").split(" ").reject(&:empty?).reject(&no_letters).map(&sterilized)
end

def no_letters
  -> word { word.chars.none?(&is_letter?) }
end

def is_letter?
  -> char { char.match(/[a-z]/i) } 
end

def sterilized
  -> word { word.scan(/[a-z']/i).join.downcase }
end