How to get a list work in RData file

If you want to keep track of the function call that produced an object,
usually you need to do that inside the function that's being called, e.g.,

test.xy <- function(x,y) {

+     xy <- x+y
+     attr(xy, "Call") <- match.call()
+     xy
+ }

xyadd <- test.xy(x=2, y=3)
xyadd

[1] 5
attr(,"Call")
test.xy(x = 2, y = 3)

str(xyadd)

 atomic [1:1] 5
 - attr(*, "Call")= language test.xy(x = 2, y = 3)


Andy

From: Xiyan Lon

Dear R-Helper,
I want to know how I get a list  work which I saved in RData
file. For
example,

 > test.xy <- function(x,y) {

+    xy <- x+y
+    xy
+ }

 >
 > xyadd <- test.xy(x=2, y=3)
 > xyadd

[1] 5

 > x1 <- c(2,43,60,8)
 > y1 <- c(91,7,5,30)
 >
 > xyadd1 <- test.xy(x=x1, y=y1)
 > xyadd1

[1] 93 50 65 38

 > save(list = ls(all=TRUE), file = "testxy.RData")
 > rm(list=ls(all=TRUE))
 > load("C:/R/useR/testxy.RData")
 > ls()

[1] "test.xy" "x1"      "xyadd"   "xyadd1"  "y1"

 >
 > ls.str(pat="xyadd")

xyadd :  num 5
xyadd1 :  num [1:4] 93 50 65 38

 >

When I run, I know the result like above

 > xyadd

[1] 5

 > xyadd1

[1] 93 50 65 38

 >

what I want to know, is there any function to make the result like:

 > xyadd

         test.xy(x=2, y=3)

and

 > xyadd1

        test.xy(x=x1, y=y1)

Best,
Xiyan Lon