为什么循环不想继续

Question

The function asks a question, the answer to which should be YES or NO. It takes the text of the question and returns the letter "y" or "n". I have a Python code, I need to transform it to Ruby.

#Python code 
def ask_yes_no(question):
    response = None
    while response not in ("y", "n"):
        respone = input(question).lower()
    return response

What did i do

# Ruby code
def ask_yes_no(question)

    guessed_it = false
    response = ""

    puts question
    loop do

        unless (response == ("y" || "n"))  || guessed_it

            response = gets.downcase
            return response #&& guessed_it == true

        end

        break if guessed_it == true 
    end
end

ask_yes_no("
How is the weather?")

Answer 1

The logic of your Ruby code isn't the same as the Python version, and would be just as incorrect in Python as it is in Ruby.

("y" || "n") is a boolean operation on two strings; since all strings are true in Ruby, the result is the first string. So therefore the result of the whole boolean operation is also true, so the unless is false, and the block is never entered.

You can use include? to do the same as the Python version:

unless ["y", "n"].include?(response) || guessed_it

but the whole Ruby version can be translated much more directly:

def ask_yes_no(question)
    puts question
    response = nil
    until ["y", "n"].include?(response) do
        response = gets.downcase.strip
    end
    response
end

Answer 2

You could also use Ruby regex's.

def ask_yes_no(question)

    until (print question; gets.chomp.downcase =~ /y|n/) do
    end

    $~.to_s

end