Ok so I have this simple class
我有一个简单的类
class Test
@var = 99
def initialize(var2)
@var2 = var2
end
attr_reader :var, :var2
end
> t = Test.new(100)
=> #<Test:0x007f9b8118ac30 @var2=100>
> t.var2
=> 100
> t.var
=> nil
Why is the last t.var statement returning nil with I expect it to return 99 because of the @var = 99 on the top of the class. Maybe my idea of scope is not 100 correct...any ideas on this one
为什么最后一个t。var语句返回nil，我希望它返回99，因为在类的顶部有@var = 99。也许我对范围的理解不是100正确……有什么想法吗
1 个解决方案
#1
9
See comments in the code.
请参阅代码中的注释。
class Test
@var = 99 # self is Test class at this point. You're defining
# an instance variable on a class instance.
def initialize(var2)
@var2 = var2 # This is normal instance variable.
end
attr_reader :var, :var2
end
t = Test.new(100)
t.var # => nil
t.var2 # => 100
# don't bother with creating an accessor and get the ivar from Test directly.
Test.instance_variable_get(:@var) # => 99
#1
9
See comments in the code.
请参阅代码中的注释。
class Test
@var = 99 # self is Test class at this point. You're defining
# an instance variable on a class instance.
def initialize(var2)
@var2 = var2 # This is normal instance variable.
end
attr_reader :var, :var2
end
t = Test.new(100)
t.var # => nil
t.var2 # => 100
# don't bother with creating an accessor and get the ivar from Test directly.
Test.instance_variable_get(:@var) # => 99