Ruby way to group anagrams in string array

问题

I implemented a function to group anagrams. In a nutshell:

input: ['cars', 'for', 'potatoes', 'racs', 'four','scar', 'creams', scream']

output: [["cars", "racs", "scar"], ["four"], ["for"], ["potatoes"],["creams", "scream"]]

I would like to know if there is a better way to do this. I really think I used too much repetition statements: until, select, delete_if. Is there any way to combine the select and delete_if statement? That means, can selected items be automatically deleted?

Code:

def group_anagrams(words)
  array = []
  until words.empty? 
    word = words.first
    array.push( words.select { |match| word.downcase.chars.sort.join.eql?(match.downcase.chars.sort.join ) } )
    words.delete_if { |match| word.downcase.chars.sort.join.eql?(match.downcase.chars.sort.join ) }
  end
  array
end

Thanks in advance,

回答1:

Like that:

 a = ['cars', 'for', 'potatoes', 'racs', 'four','scar', 'creams', 'scream']
 a.group_by { |element| element.downcase.chars.sort }.values

Output is:

[["cars", "racs", "scar"], ["for"], ["potatoes"], ["four"], ["creams", "scream"]]

If you want to you can turn this one-liner to a method of course.

回答2:

You could use the partition function instead of select, implemented in Enumerable. It splits the entries within the array according to the decision-function into two arrays.

def group_anagrams(words)
  array = []
  until words.empty? 
    word = words.first
    delta, words = words.partition { |match| word.downcase.chars.sort.join.eql?(match.downcase.chars.sort.join ) } )
    array += delta
  end
  array
end

(untested)

来源：https://stackoverflow.com/questions/9646995/ruby-way-to-group-anagrams-in-string-array

标签

ruby-on-rails

ruby

anagram