Ruby：Pig拉丁语翻译器中的字符串范围

Question

I am currently doing Test First's rspec tutorial and have a question pertaining to the Pig_Latin problem.

Specifically I want to know about string ranges. Here is a section of my code:

if phonemes.include?(word[0]) && phonemes.include?(word[1]) && phonemes.include?(word[2])
 <do something>
end

Instead of the above I tried:

if phonemes.include?(word[0..2]) # i added that character to the list of phonemes 
  <do something>                 # e.g. if the word is school i added "sch" to 
end                              # the array called phonemes

However it does not work even though "sch" is in phonemes and word[0..2] == "sch"

My question is why can I not use string ranges to manipulate the result. (i will post my full code at the bottom in case this is unclear)

Code (work in progress):

def translate(string)
array = string.split(" ")
alphabet = ("a".."z").to_a
vowels = ["a", "e", "i", "o", "u"]
phonemes = alphabet - vowels
phonemes << ["qu", "sch", "thr"]
result = []
array.each do |word|
    if vowels.include?(word[0])
        result << (word + "ay")
    elsif phonemes.include?(word[0..1])
        result << "do something"
    elsif phonemes.include?(word[0]) && phonemes.include?(word[1]) && phonemes.include?(word[2])
        result << (word[3..-1] + (word[0..2] + "ay"))
    elsif phonemes.include?(word[0]) && phonemes.include?(word[1])
        result << (word[2..-1] + (word[0..1] + "ay"))
    elsif phonemes.include?(word[0..1])
        result << "do something else"
    elsif phonemes.include?(word[0])
        result << (word[1..-1] + (word[0]+ "ay"))
    end
end
return result.join(" ")
end

As always tips to make the code more efficient would be appreciated (but the most important thing for me is to understand why string ranges aren't working). Thanks.

Answer 1

Your statement phonemes << ["qu", "sch", "thr"] is adding that array as the last element of phonemes , which is why the include? is failing. The << operator is designed to add individual elements to the array. If you want to add all the elements in that array to phonemes you can use the += operator, instead.

Answer 2

This is not an answer to your main question, but you asked for tips to improve your code. I suggest you consider using a case statement where you have your long if-else. It makes it more readable and reduces duplication. Something like this:

result << case
  when vowels.include?(word[0])
    word + "ay"
  when phonemes.include?(word[0..1])
    "do something"
  when phonemes.include?(word[0]) && phonemes.include?(word[1])
    if phonemes.include?(word[2])
      word[3..-1] + word[0..2] + "ay"
    else
      word[2..-1] + word[0..1] + "ay"
    end
  when phonemes.include?(word[0..1])
    "do something else"
  when phonemes.include?(word[0])
    word[1..-1] + word[0]+ "ay"
  else
    "do something else or raise an error if you reach this point."
end

I did not look at your code closely, but I did notice that you have phonemes.include?(word[0..1]) twice, so the second one will never be executed.