无法理解类方法和初始化

Question

我对编程很陌生，需要一些帮助来理解一些概念。我正在尝试为 Book 类创建一个方法，但不断收到“no title= method”错误。我如何或初始化什么来修复此错误？

Rspec 代码

before do
@book = Book.new
end

describe 'title' do
  it 'should capitalize the first letter' do
  @book.title = "inferno"
  @book.title.should == "Inferno"
end

这是我的代码

class Book
  def title(string)
    string.downcase!
    string_temp = string.split

    small_words = ["a", "an", "the", "at", "by", "for", "in", "of", "over",
                 "on", "to", "up", "and", "as", "but", "it", "or", "nor"]  

    string_temp.map{|word| word.capitalize! unless small_words.include?(word)}

    string_temp[0].capitalize!
    string_temp.join(" ").strip        
  end
end

Answer 1

只需创建 title= 和 title 方法：

class Book
  def title=(string)
    @title = string
  end

  def title
    @title
  end
end

这是一样的

class Book
  attr_writer :title
  attr_reader :title
end

这甚至可以简化为

class Book
  attr_accessor :title
end

但您可能会有一个编写器的自定义实现：

class Book
  def title=(string)
    @title = titleize(string)
  end

  attr_reader :title

  private

  def titleize(string)
    #...
  end
end