Question

I’m trying to assign a function for each element in a loop.
I would like the functions use the value of the variable, but they use the last value of the variable:

assign.instrumentslist = function()
{
  for(instList in lists.instruments)
  {
  assign(
      paste("test", instList, sep="."),
      function() {print(instList)},
      envir = .GlobalEnv
      )
   }
}

lists.instruments = c("CL", "HO", "GC")
assign.instrumentslist()
test.CL()
# return "GC"

thx

Answer 1

Probably this is the easiest way:

assign.instrumentslist = function() {
  for(instList in lists.instruments) {
    local({
      i <- instList
      assign(
             paste("test", instList, sep="."),
             function() {print(i)},
             pos = .GlobalEnv
             )
    })
  }
}

The key is to create local objects (i) on the function’s enclosing environment.
In this example, the environment is generated by local.

And this is a really really bad hack:

lapply(lists.instruments, 
  function(x) .GlobalEnv[[paste("test1", x, sep=".")]] <- function() print(x))