如何将键和值推入空的散列瓦特/红宝石？ [英] How to push keys and values into an empty hash w/ Ruby?

问题描述

我有一个字典类，希望能够使用'add'方法将键（作为关键字）和值（作为定义）推送到空的散列中。我不明白如何在语法上编写它。

红宝石：

我也包含了一个RSPEC文件。  class Dictionary 
 attr_accessor：关键字，定义
 def entries 
 @hash = {} 
 end 
 def add（options）
 options.map do | keyword，definition | 
 @hash [keyword.to_sym] =定义
结束
结束
结束
  

Rspec

  require'dictionary'
 
在do 
 @d = Dictionary.new 
 end 
之前描述Dictionary do 
它可以用关键字和定义添加整个条目'do 
 @ d.add （'鱼'=>'水生动物'）
 @ d.entries.should == {'fish'=> 'aquatic animal'} 
 @ d.keywords.should == ['fish'] 
 end 
  

任何帮助表示赞赏。谢谢！

更新：
谢谢戴夫牛顿回复。我使用了你的代码，并得到这个错误：

错误：

  *失败/错误：@ d.keywords.should == ['fish'] 
 NoMethodError：
未定义方法关键字for＃<字典：0x007fb0c31bd458 
 @hash = {fish=>aquatic animal}> * 
  

当我使用@hash [word.to_sym] = defintion

  *将'word'转换为符号时出现不同的错误* Failure / Error ：@ d.entries.should == {'fish'=> 'aquatic animal'} 
 expected：{fish=>aquatic animal} 
 got：{：fish =>aquatic animal}（使用==）
 Diff ：
 @@ -1,2 +1,2 @@ 
  - fish=> 水生动物
 +：鱼=> 水生动物* 
  

解决方案

c $ c> Dictionary 的初始化：

  class Dictionary 
 def initialize 
 @hash = {} 
 end 
 
 def add（defs）
 defs.each do | word，definition | 
 @hash [word] = definition 
 end 
 end 
 end 
  

现在，除非您调用条目，否则没有散列。

条目应该返回现有的哈希，而不是创建一个新的哈希。

关键字应该返回哈希键。

您不需要关键字和定义。这样的单项在词典课上没有意义。您可能需要像 lookup（word）这样的返回定义。

另外，您将单词转换为符号，但我不知道为什么–特别是因为您在规范中使用了字符串键。选择一个，虽然我不相信这是符号增加价值的情况。

请仔细考虑变量命名以提供尽可能多的上下文。

I have a dictionary class and want to be able to push keys (as keywords) and values (as definitions) into an empty hash with an 'add' method. I don't understand how to syntactically write that. I have included an RSPEC file too.

ruby:

 class Dictionary
     attr_accessor :keyword, :definition
     def entries
          @hash = {}
     end
     def add(options)
          options.map do |keyword, definition|
               @hash[keyword.to_sym] = definition
          end
     end
 end

Rspec:

 require 'dictionary'

   describe Dictionary do
   before do
       @d = Dictionary.new
   end
   it 'can add whole entries with keyword and definition' do
       @d.add('fish' => 'aquatic animal')
       @d.entries.should == {'fish' => 'aquatic animal'}
       @d.keywords.should == ['fish']
   end

Any help is appreciated. Thank you!

UPDATE: Thank you Dave Newton for replying. I used your code and got this error:

ERROR:

 *Failure/Error: @d.keywords.should == ['fish']
 NoMethodError:
 undefined method `keywords' for #<Dictionary:0x007fb0c31bd458 
 @hash={"fish"=>"aquatic animal"}>*

I get a different error when I convert 'word' into a symbol using @hash[word.to_sym] = defintion

 *Failure/Error: @d.entries.should == {'fish' => 'aquatic animal'}
   expected: {"fish"=>"aquatic animal"}
        got: {:fish=>"aquatic animal"} (using ==)
   Diff:
   @@ -1,2 +1,2 @@
   -"fish" => "aquatic animal"
   +:fish => "aquatic animal"*

解决方案

Instantiate your hash in Dictionary's initialize:

class Dictionary
  def initialize
    @hash = {}
  end

  def add(defs)
    defs.each do |word, definition|
      @hash[word] = definition
    end
  end
end

Right now you have no hash until you call entries, which you don't.

entries should return the existing hash, not create a new one.

keywords should return the hash's keys.

You do not need accessors for keyword and definition. Such singular items are meaningless in a dictionary class. You might want something like lookup(word) that returned a definition.

Also, you convert words to symbols, but I don't know why–particularly since you use string keys in your spec. Pick one, although I'm not convinced this is a case where symbols add value.

Please consider variable naming carefully to provide as much context as possible.

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