为什么循环不想继续

Question

function 提出一个问题，答案应该是“是”或“否”。 它接受问题的文本并返回字母“y”或“n”。 我有一个 Python 代码，我需要将其转换为 Ruby。

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

我做了什么

# 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")是对两个字符串的 boolean 操作； 由于 Ruby 中的所有字符串都为真，因此结果是第一个字符串。 所以因此整个 boolean 操作的结果也是真的，所以unless是假的，并且永远不会进入块。

你可以使用include? 与 Python 版本相同：

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

但是整个 Ruby 版本可以更直接地翻译：

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

Answer 2

您也可以使用 Ruby 正则表达式。

def ask_yes_no(question)

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

    $~.to_s

end