r - Need a workaround for copying a data.table in a reference class-CodePudding

I'm trying to copy a data table within a reference class but I'm unable to do so. Here is a small example

library(data.table)

Example <- setRefClass("Example",
                   fields = list(
                     data1 = "data.table"
                   ),
                   
                   method = list(
                     tryToCopyData1 = function(){
                       data_temp <- copy(data1)
                     }
                     )
                   )

example <- Example$new()

example$data1 <- data.table(x=rep(c("a","b","c"),each=3), y=c(1,3,6), v=1:9)

example$tryToCopyData1()

When I do this I get the following error

Error in if (shallow) assign(field, get(field, envir = selfEnv), envir = vEnv) else { : argument is not interpretable as logical In addition: Warning message: In if (shallow) assign(field, get(field, envir = selfEnv), envir = vEnv) else { : the condition has length > 1 and only the first element will be used

Any ideas of how I can get around this? I ultimately just need to manipulate the data table within the function without changing the original field value.

Thank you!

CodePudding user response：

You should use data.table::copy instead of the default reference class copy method:

library(data.table)

Example <- setRefClass("Example",
                       fields = list(
                         data1 = "data.table"
                       ),
                       
                       method = list(
                         tryToCopyData1 = function(){
                           data_temp <- data.table::copy(data1)
                         }
                       )
)

example <- Example$new()

example$data1 <- data.table(x=rep(c("a","b","c"),each=3), y=c(1,3,6), v=1:9)

example$tryToCopyData1()