CODEWITHSUNDEEP
ruby
Muhammad_Sigit_Dude
Muhammad_Sigit_Dude

Reputation: 77

how to check if two string contains the same character in ruby

I want to make a word unscarambler in ruby. say if I have a words in array

 words = ["foo","ofo"]

how can I compare this to another string like "oof" and returning true value

Upvotes: 1

Views: 3352

Answers (2)

Cary Swoveland
Cary Swoveland

Reputation: 110755

This can be done as follows.

words = ["foo", "ofo", "goo"]
target = "foo"
target_size = target.size
  #=> 3 
target_sorted = target.each_char.sort
  #=> ["f", "o", "o"] 

words.select { |w| anagram?(target_size, target_sorted, w) }
  #=> ["foo", "ofo"]

The typical way anagram? is written is:

def anagram?(target_size, target_sorted, w)
  return false unless w.size == target_size
  w.each_char.sort == target_sorted
end

However, I've wondered it might be faster to:

  • Step through the characters of target
  • Search for the index i of a matching character in w
  • If a match is found, delete w[i]
  • if no match is found (i #=> nil), return false
  • return true if false is not returned earlier

This can be implemented thus:

def anagram?(target_size, target, w)
  return false unless target.size == w.size
  wcpy = w.dup
  target.each_char do |c|
    i = wcpy.index(c)
    return false unless i
    wcpy[i] = ''
  end
  true
end

words.select { |w| anagram?(target_size, target, w) }
  #=> ["foo", "ofo"]

I'll have to benchmark the two one day.

We could also write: 

def anagram?(w1, w2)
  return false unless w1.size == w2.size
  w1.chars.difference(w2.chars).empty?
end

The helper Array#difference is defined here.

Upvotes: 2

user4426213
user4426213

Reputation:

If all the strings in the array are permutations of each other then:

words = ["foo", "ofo"]
str = "foo"

words[0].split("").sort == str.split("").sort

Upvotes: 1

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