从插槽上的许多实例中选择一个类的实例？-selectinstanceofaclassfrommanyinstancesconditionedonaslot?

Assume I have several instances of an S4 class, just like in this example.

假设我有几个S4类的实例，就像在这个例子中一样。

setClass("myClass",representation(name = "character",
          description = "character")

my1 <- new("myClass",name = "my1",description = "Some test.")
my2 <- new("myClass",name = "my2",description = "Some try.")
my3 <- new("myClass",name = "my3",description = "Some more elaborate test.")

I would like to give back the name of all classes (i.e. name slot or object name) that contains the word test. If I just use grep on single slot it does work partly:

我想回馈包含单词test的所有类（即名称槽或对象名称）的名称。如果我只在单个插槽上使用grep它可以部分工作：

grep("test",my1@description,value=T)

I end up with the whole expresion "Some test". Of course I could put all of these slots in a list and apply over them. But still I'd just end up with the description itself without knowing to which name they belong.

我最终得到了整个表达“一些测试”。当然，我可以将所有这些插槽放在一个列表中并应用它们。但是我仍然会在不知道它们属于哪个名称的情况下结束描述本身。

So, how can I find the instances I want?

那么，我怎样才能找到我想要的实例呢？

Would you rather organize a bunch of instances of a class in a separate environment or a list of Instances?

您是否愿意在单独的环境或实例列表中组织一组类的实例？

1 个解决方案

unlist(eapply(.GlobalEnv,
              function(x)
                if (class(x)[1] == "myClass")
                  if (any(grep("test", x@description))) return(x@name)))

  my1   my3 
"my1" "my3"