ruby 如何在我的 .rb 文件中共享变量？
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How to share variables across my .rb files?
提问by Radek
I have a few .rbfiles and I want to use the same variables in all of them. Let's say variable test_variable = "test"should be accessible from all my .rbfiles. How can I achieve that?
我有几个.rb文件，我想在所有文件中使用相同的变量。假设变量test_variable = "test"应该可以从我的所有.rb文件中访问。我怎样才能做到这一点？
I created settings.rbfile with test_variable = "test"then used require 'settings'in another .rbfile, but it didn't work. I would like to use requirenot load.
我创建了settings.rb文件，test_variable = "test"然后require 'settings'在另一个.rb文件中使用，但它不起作用。我想用requirenot load。
I tried to make the variable global by prefixing the variable name with $, but I am still getting undefined local variable or method 'test_variable' for main:Object (NameError).
我试图通过在变量名前加上前缀来使变量成为全局变量$，但我仍然得到undefined local variable or method 'test_variable' for main:Object (NameError).
回答by Phrogz
Constants (which include modules and classes) are added to the shared global environment:
phrogz$ cat constants1.rb TEST_VARIABLE = "test" phrogz$ cat constants2.rb require_relative 'constants1' p TEST_VARIABLE phrogz$ ruby constants2.rb "test"Instance variables declared in main are all part of the same
main:phrogz$ cat instance1.rb @test_variable = "test" phrogz$ cat instance2.rb require_relative 'instance1' p @test_variable phrogz$ ruby instance2.rb "test"Global variables are also all part of the same environment (tested in 1.8.6, 1.8.7, and 1.9.2):
phrogz$ cat global1.rb $test_variable = "test" phrogz$ cat global2.rb require_relative 'global1' p $test_variable, RUBY_DESCRIPTION phrogz$ ruby global2.rb "test" "ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-darwin10.7.0]"
常量（包括模块和类）被添加到共享的全局环境中：
phrogz$ cat constants1.rb TEST_VARIABLE = "test" phrogz$ cat constants2.rb require_relative 'constants1' p TEST_VARIABLE phrogz$ ruby constants2.rb "test"在 main 中声明的实例变量都是相同的一部分
main：phrogz$ cat instance1.rb @test_variable = "test" phrogz$ cat instance2.rb require_relative 'instance1' p @test_variable phrogz$ ruby instance2.rb "test"全局变量也是同一个环境的一部分（在 1.8.6、1.8.7 和 1.9.2 中测试过）：
phrogz$ cat global1.rb $test_variable = "test" phrogz$ cat global2.rb require_relative 'global1' p $test_variable, RUBY_DESCRIPTION phrogz$ ruby global2.rb "test" "ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-darwin10.7.0]"
回答by Linuxios
Ruby will nevershare local variables between files. You can wrap them in a Module though:
Ruby永远不会在文件之间共享局部变量。您可以将它们包装在一个模块中：
module SharedVaribles
@test_var="Hello, World"
def self.test_var
return @test_var
end
def self.test_var=(val)
@test_val=val;
end
end
Put that in settings.rb, requireit into all your files, and use SharedVaribles.test_varand SharedVaribles.test_var=to access the variable. Remember, Ruby's requireis nothing like C's #include, it is much more complex. It executes the file, then imports all constants, modules, and classes to the requireer.
把在settings.rb，require它为您的所有文件，并使用SharedVaribles.test_var和SharedVaribles.test_var=访问的变量。请记住，Rubyrequire与 C 完全不同#include，它要复杂得多。它执行文件，然后将所有常量、模块和类导入到requireer。
回答by logical_proof
module Foo
attr_accessor :test_var
def initialize
@test_var = "hello world"
end
end
Create the module with your variable or variables in your config file and then include the module in whatever class you intend to use.
在配置文件中使用您的一个或多个变量创建模块，然后将该模块包含在您打算使用的任何类中。
require_relative 'foomod.rb'
class Bar
include Foo
end
foobar = Bar.new
foobar.test_var = "goodbye"
puts foobar.test_var
Each instance of the class will initialize with whatever value you would like.
该类的每个实例都将使用您想要的任何值进行初始化。
回答by Gerard Simpson
You shouldn't need to wrap these variables in a module.
您不需要将这些变量包装在module.
Simply adding them to another_file.rband using require_relative 'another_file'(if it's in the same directory) or require 'path/to/another_file'should be sufficient to share those variables across files.
简单地将它们添加到another_file.rb并使用require_relative 'another_file'（如果它在同一目录中）或者require 'path/to/another_file'应该足以跨文件共享这些变量。
