从 S4 类定义中的包中识别 S3 (?) 类
我在从 S4 类定义识别旧包中获取类时遇到一些麻烦。我不断收到错误
Error in makePrototypeFromClassDef(properties, ClassDef, immediate, where) :
in making the prototype for class "Tsvmm" elements of the prototype failed to
match the corresponding slot class: dates (class "dates" )
In addition: Warning message:
undefined slot classes in definition of "Tsvmm": dates(class "dates")
一个可重现的示例：
require(chron)
setClass(
Class="Tsvmm",
representation=representation(
data = "data.frame",
dates = "dates"
),
prototype=prototype(
data = data.frame(),
dates = chron(0)
)
)
尝试class(chron(0))时，答案是“dates”“times”。使用is.numeric(chron(0))，答案是TRUE。然而，当我将槽日期的类别设置为“numeric”时，我收到相同的错误，但没有警告消息。
我感觉我忽略了一些明显的东西，但我在文档中还找不到它。有人指点一下吗？
PS：我知道 chron 包至少很奇特，但我有充分的理由使用它。另外，其他软件包也可能会出现此问题。将此作为一般问题的示例。所以请不要告诉我使用 Date 或 POSIXt 类。这是我现在正在使用的一个技巧。
I have some troubles getting a class from an older packages been recognized by the S4 class definition. I keep on getting the error
Error in makePrototypeFromClassDef(properties, ClassDef, immediate, where) :
in making the prototype for class "Tsvmm" elements of the prototype failed to
match the corresponding slot class: dates (class "dates" )
In addition: Warning message:
undefined slot classes in definition of "Tsvmm": dates(class "dates")
A reproducible example:
require(chron)
setClass(
Class="Tsvmm",
representation=representation(
data = "data.frame",
dates = "dates"
),
prototype=prototype(
data = data.frame(),
dates = chron(0)
)
)
When trying class(chron(0)), the answer is "dates" "times". using is.numeric(chron(0)), the answer is TRUE. Yet, when I set the class of slot dates as "numeric", I get the same error without the warning message.
I have the feeling I'm overlooking something obvious, but I couldn't find it in the documentation yet. Anybody any pointers?
PS: I know the chron package is at least peculiar, but I have good reasons to use this. Plus, the problem is likely to occur with other packages. See this as an example for a general question. So please, don't tell me to use the Date or POSIXt classes. That's a hack I'm using now.
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看来您需要 setOldClass 使方法相信日期是一个真正的班级。
It seems that you need setOldClass to make methods believe dates is a real class.
我遇到了类似的问题，因为 Gtk2 对象（例如，Gtk2::GtkBuilder）不是 S4 类，而我希望在我自己的代码中拥有这样一个对象的一个实例。我想我通过删除原型（）的东西并使用“initialize（）”方法来解决这种情况。
I've got a similar problem because Gtk2 objects (e.g., Gtk2::GtkBuilder) are not S4 classes whereas I wanted one instance of such an object in my own code. I think I worked arround a the situation by removing the prototype() thing and using an "initialize()" method.