[R] When customizing last line, the code stops working

[Frank S.]

A clarification regarding my previous post for those ineterested in the issue:


Looking carefully at Duncan's solution, the key point would be introducing envir = environment()

as argument of lapply function (the default envir of do.call function is parent.frame() ).

)

 union <- do.call(
               what = rbind,
               args = lapply(
                        X = paste0("dt_sp_", 1:length(sp)),
                        FUN = get,
                       envir = environment()
                       )
 )


________________________________
De: Frank S.
Enviado: viernes, 4 de noviembre de 2016 12:33:11
Para: Duncan Murdoch; r-help at r-project.org; Mark.Fowler at dfo-mpo.gc.ca
Asunto: Re: [R] When customizing last line, the code stops working


[[elided Hotmail spam]]


As Duncan Murdoch indicated in his answer, it was a matter of envir argument from function do.call.


Thank you!


Frank S.

________________________________
De: Duncan Murdoch <murdoch.duncan at gmail.com>
Enviado: jueves, 3 de noviembre de 2016 14:41:26
Para: Frank S.; r-help at r-project.org
Asunto: Re: [R] When customizing last line, the code stops working

On 03/11/2016 8:29 AM, Frank S. wrote:
> Dear all,
>
>
> The function I present works perfectly when I run it as written (that is, leaving NEW LINE as commented). However, when
>
> I try to run the same function via this mentioned line (and therefore commenting LAST LINE) R gives an error message:
> Error in FUN(X[[i]], ...) : object 'dt_sp_1' not found. I do not understand why I don't get the same result.

You aren't specifying the "envir" argument to "get", so it defaults to
the environment from which you called get, and that's the evaluation
frame of lapply() (or maybe of do.call()).

Write the last line as

union <- do.call(rbind, lapply(paste0("dt_sp_", 1:length(sp)), get, envir = environment()))


and it works.

Duncan Murdoch
>
>
[[elided Hotmail spam]]
>
>
> Frank S.
>
>
> all.sp <- function(age.u, open, close) {
>
> require(data.table)
> dt <- data.table( id = c(rep(1, 2), 2:4, rep(5, 2)),
>     sex = as.factor(rep(c(0, 1), c(3, 4))),
>     fborn =  as.Date(c("1935-07-25", "1935-07-25", "1939-07-23", "1943-10-05",
>                        "1944-01-01", "1944-09-07", "1944-09-07")) )
>
> sp <- seq(open, close, by = "year")
> dt_sp <- list()
> for (i in 1:length(sp)) {
>    vp <- as.POSIXlt(c(as.Date("1000-01-01"), sp))
>    vp$year <- vp$year - age.u
>    dt.cut <- as.numeric(cut(x = as.POSIXlt(dt$fborn), breaks = vp, right = TRUE, include.lowest = TRUE))
>    dt_sp[i] <- split(dt, factor(dt.cut, i))
>    dt_sp[[i]] <- data.table(dt_sp[[i]])[, entry_sp := sp[i]]
>    assign(paste0("dt_sp_", 1:length(sp))[i], dt_sp[[i]])
>    }
>
>    union <- rbind(dt_sp_1, dt_sp_2, dt_sp_3, dt_sp_4)     # LAST LINE: IT WORKS
>
>
>    # I TRY TO CUSTOMIZE LAST LINE, BUT THEN CODE STOPS WORKING
>    # union <- do.call(rbind, lapply(paste0("dt_sp_", 1:length(sp)), get))     # NEW LINE
> }
>
> # Example:
> result <- all.sp(age.u = 65, open = as.Date("2007-01-01"), close = as.Date("2010-05-01"))
>
>        [[alternative HTML version deleted]]
>
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