Question

这是我的带有哈希值的红宝石文件：

book.rb

class Book
  attr_accessor :title, :author, :language, :classification, :isbn, :book_id, :borrow_status



  def initialize(title, author, language, classification, isbn, book_id, borrow_status)
    @title = title
    @author = author
    @language = language
    @classification = classification
    @isbn = isbn
    @book_id = book_id
    @borrow_status = borrow_status
  end

  def bookid
    @book_id
  end

  def booklist
    @title = @title.split(/ |\_|\-/).map(&:capitalize).join(" ")
    @author = @author.split(/ |\_|\-/).map(&:capitalize).join(" ")
    @language = @language.capitalize
    @isbn.to_s
    @book_id.to_s

    {
        :Title => @title,
        :Author => @author,
        :Language => @language,
        :Classification => @classification,
        :ISBN => @isbn,
        :Book_ID => @book_id,
        :Status => @borrow_status,
    }
  end


end

现在，我已经有五个键值对用于此哈希，它们位于名为 top.rb 的红宝石文件中：

$books1 = Book.new("lonely planet: ireland","damian harper","english","tourism",9781786574459,1,"available")
$books2 = Book.new("ninteen eighty four","george orwell","english","literature",9781374677817, 2,"available")
$books3 = Book.new("japanese in 30 days","naomi ono","japanese","education",9787928365729,3,"available")
$books4 = Book.new("brand famous: how to get everyone talking about your business","linzi boyd","english","business",9780857084903,4,"borrowed")
$books5 = Book.new("SQL in 10 mins","ming zhong, xiaoxia liu","chinese","hi tech",9787115313980,5,"unavailable")

并使用以下方法输出结果：

    def status
      bookstatus = gets.chomp.to_s
      if bookstatus == "status"
       puts "Status:" + "\n" + "#{$books1.booklist[:Book_ID]}: #{$books1.booklist[:Title]}: #{$books1.booklist[:Status]}"
       puts "#{$books2.booklist[:Book_ID]}:#{$books2.booklist[:Title]}: #{$books2.booklist[:Status]}"
       puts "#{$books3.booklist[:Book_ID]}:#{$books3.booklist[:Title]}: #{$books3.booklist[:Status]}"
       puts "#{$books4.booklist[:Book_ID]}:#{$books4.booklist[:Title]}: #{$books4.booklist[:Status]}"
       puts "#{$books5.booklist[:Book_ID]}:#{$books5.booklist[:Title]}: #{$books5.booklist[:Status]}"
   else
       puts "error"
end
end

现在，我将添加更多值，让用户输入书籍的信息（例如title = gets.chomp.to_s），并为添加的书籍创建新的键值对

据我所知，将新的键值对添加到ruby如下：

my_hash = {:a => 5}
my_hash[:key] = "value"

但是，book.rb中的哈希没有任何名称，我试图给它起一个类似名称

book_list = {
        :Title => @title,
        :Author => @author,
        :Language => @language,
        :Classification => @classification,
        :ISBN => @isbn,
        :Book_ID => @book_id,
        :Status => @borrow_status,
    }

它将输出错误。

我的问题是，我想知道如何向没有名称的红宝石文件中的哈希添加新的键值对？ < / p>

谢谢。

Answer 1

将booklist方法更改为此将解决您的直接问题：

SELECT uos.uid,
       uos.value,
       uos.action_key
FROM   (SELECT action_key,
               Max(createddate) AS maxcreateddate
        FROM   usersoptstatus 
        WHERE uid = 1607 
        GROUP  BY action_key) A
INNER JOIN usersoptstatus AS uos
  ON uos.action_key = A.action_key AND 
     uos.createddate = A.maxcreateddate
WHERE  uos.uid = 1607
ORDER  BY uos.id DESC;

现在您可以def booklist @booklist ||= { :Title => @title.split(/ |\_|\-/).map(&:capitalize).join(" "), :Author => @author.split(/ |\_|\-/).map(&:capitalize).join(" "), :Language => @language.capitalize, :Classification => @classification, :ISBN => @isbn.to_s, :Book_ID => @book_id.to_s, :Status => @borrow_status, } end了。

您问题中的代码有很多“你好，世界！”级别的错误，看来您似乎仍然需要了解一些Ruby基础知识，例如使用变量，booklist[:Xyz] = 'xyz'，@isbn，isbn，{{1} }或$isbn等

网上有比我准备好的更好的“学习红宝石”教程，所以我的回答可能不是很有帮助。

如何将键值对添加到没有名称的哈希中？

1 个答案: