有沒有辦法將R6物件分配給S4物件槽？-有解無憂

正如主題描述的那樣，我正在尋找一種方法來實作這一點：

require("R6")
R6cls <- R6::R6Class("R6obj",
    public = list(val = 1, foo = function() "foo!")
)
# check this R6 class
r6o <- R6cls$new()
r6o

# <R6obj>
#  Public:
#    clone: function (deep = FALSE) 
#    foo: function () 
#    val: 1

# now the S4 part 
S4wR6slot <- function() new("S4wR6slot")
setClass("S4wR6slot", contains = "environment", # or maybe "R6" or "R6cls"? tried them all but none seemed to work
         slots = list(a = "R6cls", b = "character"))
   
# Currently gives
Warning message:
undefined slot classes in definition of "S4wR6slot": a(class "R6cls") 
# but you can still kind of use it 
s4r6 <- S4wR6slot()
s4r6

# An object of class "S4wR6slot"
# <environment: 0x00000179de2da628>
# Slot "a":
# NULL
#
# Slot "b":
# character(0)
s4r6@b <- "text" # works nicely 
# BUT trying to assign to that env slot 
s4r6@a <- r6o

# will throw these "ugly" errors 
Error in (function (cl, name, valueClass)  : 
  c("assignment of an object of class “R6obj” is not valid for @‘a’ in an object of class “S4wR6slot”; is(value, \"R6cls\") is not TRUE", 
"assignment of an object of class “R6” is not valid for @‘a’ in an object of class “S4wR6slot”; is(value, \"R6cls\") is not TRUE")

玩弄setOldClass()也沒有什么好處。也許根本沒有辦法讓這項作業 - 只是詢問某人是否有想法？或者甚至可以實作這一點 - 否則也許我的 rtfm 不夠好，有人可以指出我的檔案，它說你不應該嘗試完成這項作業？

uj5u.com熱心網友回復：

有一種方法可以在 S4 類中包含一個 R6 物件，但涉及通過定義一個S4名為“R6”的類來欺騙 S4 系統。這將防止methods包抱怨 R6 類不存在。幸運的是，它實際上并沒有檢查原型中的“R6”物件是否為 S4 型別，允許您將實際的 R6 物件粘貼到其中。

library(R6)

R6cls <- R6::R6Class("R6obj",
                     public = list(val = 1, foo = function() "foo!")
)

setClass('R6')

setClass("S4wR6slot", slots = list(a = 'R6', b = "character"),
         prototype = list(a = R6cls$new(), b = 'Hello'))

S4wR6slot <- function() new("S4wR6slot")

myS4 <- S4wR6slot()

class(myS4)
#> [1] "S4wR6slot"
#> attr(,"package")
#> [1] ".GlobalEnv"

isS4(myS4)
#> [1] TRUE

myS4@a
#> <R6obj>
#>   Public:
#>   clone: function (deep = FALSE) 
#>     foo: function () 
#>       val: 1

uj5u.com熱心網友回復：

我還為這個簡單的示例類找到了一個似乎可行的解決方案 - 但遺憾的是，該解決方案有趣地失敗/失敗了更復雜的 R6 類。

在此處添加該示例解決方案以確保完整性

require(R6)
R6cls <- R6::R6Class("R6obj",
                     public = list(val = 1, foo = function() "foo!")
)
# check this R6 class
r6o <- R6cls$new()
r6o

# <R6obj> # <- I SUDDENLY NOTICED THIS on a second look! 
#   Public:
#     clone: function (deep = FALSE) 
#     foo: function () 
#    val: 1

S4wR6slot <- function() new("S4wR6slot")

setClass("S4wR6slot", contains = "environment",
         slots = list(a = "R6obj" , b = "character"))
# list(a = "R6obj" ... is what did the "magic"

s4r6 <- S4wR6slot()
s4r6

# An object of class "S4wR6slot"
# <environment: 0x000002520292f470>
# Slot "a":
# NULL
#
# Slot "b":
# character(0)

s4r6@b <- "text"
s4r6@a <- r6o # THIS THEN WORKED/WORKS! 

class(r6o)
# [1] "R6obj" "R6" # I simply used that "R6obj" in the S4 definition above
is(r6o, "R6")
# [1] TRUE
is(r6o, "R6obj")
# [1] TRUE

但不知何故，“Robj”類（型別）在更復雜的設定中丟失了，即我正在使用在另一個包中的一個包中定義的 R6 類，然后“R6obj”不再可供使用。:-(

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標籤：r s4 r6

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