Ruby：如何制作公共静态方法？
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Ruby: How to make a public static method?
提问by Tom
In Java I might do:
在 Java 中，我可能会这样做：
public static void doSomething();
And then I can access the method statically without making an instance:
然后我可以静态访问该方法而无需创建实例：
className.doSomething();
How can I do that in Ruby? this is my class and from my understanding self.makes the method static:
我怎样才能在 Ruby 中做到这一点？这是我的课程，根据我的理解self.，该方法是静态的：
class Ask
def self.make_permalink(phrase)
phrase.strip.downcase.gsub! /\ +/, '-'
end
end
But when i try to call:
但是当我尝试打电话时：
Ask.make_permalink("make a slug out of this line")
I get:
我得到：
undefined method `make_permalink' for Ask:Class
Why is that if i haven't declared the method to be private?
如果我没有将方法声明为私有，为什么会这样？
回答by devanand
Your given example is working very well
您给出的示例运行良好
class Ask
def self.make_permalink(phrase)
phrase.strip.downcase.gsub! /\ +/, '-'
end
end
Ask.make_permalink("make a slug out of this line")
I tried in 1.8.7 and also in 1.9.3 Do you have a typo in you original script?
我在 1.8.7 和 1.9.3 中都试过你的原始脚本有错别字吗？
All the best
祝一切顺利
回答by Ivailo Bardarov
There is one more syntax which is has the benefit that you can add more static methods
还有一种语法的好处是您可以添加更多静态方法
class TestClass
# all methods in this block are static
class << self
def first_method
# body omitted
end
def second_method_etc
# body omitted
end
end
# more typing because of the self. but much clear that the method is static
def self.first_method
# body omitted
end
def self.second_method_etc
# body omitted
end
end
回答by jefflunt
Here's my copy/paste of your code into IRB. Seems to work fine.
这是我将您的代码复制/粘贴到 IRB 中的内容。似乎工作正常。
$ irb
1.8.7 :001 > class Ask
1.8.7 :002?>
1.8.7 :003 > def self.make_permalink(phrase)
1.8.7 :004?> phrase.strip.downcase.gsub! /\ +/, '-'
1.8.7 :005?> end
1.8.7 :006?>
1.8.7 :007 > end
=> nil
1.8.7 :008 > Ask.make_permalink("make a slug out of this line")
=> "make-a-slug-out-of-this-line"
Seems to work. Test it out in your irbas well, and see what results you're getting. I'm using 1.8.7 in this example, but I also tried it in a Ruby 1.9.3 session and it worked identically.
似乎工作。也在你的irb身上测试一下，看看你得到了什么结果。我在这个例子中使用了 1.8.7，但我也在 Ruby 1.9.3 会话中尝试过它，它的工作原理相同。
Are you using MRI as your Ruby implementation (not that I think that should make a difference in this case)?
您是否使用 MRI 作为您的 Ruby 实现（不是我认为在这种情况下应该有所作为）？
In irbmake a call to Ask.public_methodsand make sure your method name is in the list. For example:
在irb调用Ask.public_methods并确保您的方法名称在列表中。例如：
1.8.7 :008 > Ask.public_methods
=> [:make_permalink, :allocate, :new, :superclass, :freeze, :===,
...etc, etc.]
Since you also marked this as a ruby-on-railsquestion, if you want to troubleshoot the actual model in your app, you can of course use the rails console: (bundle exec rails c) and verify the publicness of the method in question.
由于您也将此标记为ruby-on-rails问题，因此如果您想对应用程序中的实际模型进行故障排除，您当然可以使用 rails 控制台：( bundle exec rails c) 并验证所讨论方法的公开性。
回答by K M Rakibul Islam
I am using ruby 1.9.3 and the program is running smoothly in my irb as well.
我正在使用 ruby 1.9.3 并且该程序在我的 irb 中也运行顺利。
1.9.3-p286 :001 > class Ask
1.9.3-p286 :002?> def self.make_permalink(phrase)
1.9.3-p286 :003?> phrase.strip.downcase.gsub! /\ +/, '-'
1.9.3-p286 :004?> end
1.9.3-p286 :005?> end
=> nil
1.9.3-p286 :006 > Ask.make_permalink("make a slug out of this line")
=> "make-a-slug-out-of-this-line"
It's also working in my test script. Nothing wrong with your given code.It's fine.
它也适用于我的测试脚本。您给定的代码没有问题。没关系。
