类名称的 Ruby 未初始化常量名称错误
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Ruby Uninitialized Constant NameError for Class Name
提问by Victor Xiong
I want to inherit a sub-class from a parent-class.
我想从父类继承子类。
Here is my code. 3 classes are created in 3 separate files.
这是我的代码。在 3 个单独的文件中创建了 3 个类。
class Transportation
#codes
end
class Plane < Transportation
#codes
end
class Boat < Transportation
#codes
end
And when I was running this code, I got the error for Boat, but no issue for Plane when I only have Plane created:
当我运行这段代码时，我收到了关于船的错误，但是当我只创建了飞机时，飞机没有问题：
uninitialized constant Transportation (NameError)
Can anyone help me with this issue?
谁能帮我解决这个问题？
Thanks
谢谢
回答by vgoff
There is no reason for this code to fail, unless the definition of Transportationis in another file.
这段代码没有理由失败，除非 的定义Transportation在另一个文件中。
If that is the case, and these are in different files, don't forget to require the file with the Transportationclass before the other file with the usage in it.
如果是这种情况，并且这些文件位于不同的文件中，请不要忘记Transportation在包含用法的其他文件之前require 带有类的文件。
As you mentioned, there are three different files.
正如您所提到的，有三个不同的文件。
You can create a file that has the required libraries. Perhaps it is in your bin/transport_simulator.rbfile.
您可以创建一个包含所需库的文件。也许它在您的bin/transport_simulator.rb文件中。
require 'transportation'
require 'boat'
require 'plane'
Now they will be required in the proper order, and the files with the classes that subclass Transportation will know about that class.
现在，它们将以正确的顺序被需要，并且带有子类 Transportation 的类的文件将了解该类。
