I want to get access to the code of an S4 method in order to possibly modify
a function to accomplish my particular needs: in my case the function in is
cenfit() from the package NADA
Now, given my reproducible example:
my.ex<-structure(list(TEC = c(0.21, 0.077, 0.06, 0.033, 0.014, 0.0072), LR
c(0L, 0L, 1L, 0L, 1L, 0L)), .Names = c("TEC", "LR"), class =
"data.frame",
row.names = c(NA, -6L))
and the following few lines of code:
library(?NADA)
attach(my.ex)
cenfit(TEC,LR)
giving this output:
n n.cen median mean sd
6.00 2.00 0.033 0.058 0.083
I would like to add one more result to the above, namely ?sum?, very simply
computed as the product of ?n? times ?mean?
Do you think that is possible or convenient?
I?ve been reading that editing a S4 methods needs particular attention as by
using showMethods("cenfit") and then getMethod("cenfit"); in
fact, I?ve been
trying that but without much success (i.e. understanding of the cumbersome
output)
can anyone give me some help on how is probably better to proceed in order
to get my new result?
different alternative solutions or hints or advices are also more than
welcomed
(I?m pretty new on R and specially on the field of function handling and
customizing)
all the best
max
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Hi,
Your reproducible example isn't reproducible for me, as I get an error
message.
But regardless, the easiest thing to do is write your own wrapper,
something like:
mycenfit <- function(x, y) {
result <- cenfit(x, y)
c(result, sum = result$n * result$mean)
}
No need to change anything in the package itself. Incidentally, using
attach() is generally a really bad idea. with() is much safer.
Sarah
On Thu, Nov 15, 2012 at 7:00 AM, maxbre <mbressan at arpa.veneto.it>
wrote:> I want to get access to the code of an S4 method in order to possibly
modify
> a function to accomplish my particular needs: in my case the function in is
> cenfit() from the package NADA
>
> Now, given my reproducible example:
>
> my.ex<-structure(list(TEC = c(0.21, 0.077, 0.06, 0.033, 0.014, 0.0072),
LR > c(0L, 0L, 1L, 0L, 1L, 0L)), .Names = c("TEC", "LR"),
class = "data.frame",
> row.names = c(NA, -6L))
>
> and the following few lines of code:
>
> library(?NADA)
>
> attach(my.ex)
>
> cenfit(TEC,LR)
>
> giving this output:
>
> n n.cen median mean sd
> 6.00 2.00 0.033 0.058 0.083
>
> I would like to add one more result to the above, namely ?sum?, very simply
> computed as the product of ?n? times ?mean?
>
> Do you think that is possible or convenient?
>
> I?ve been reading that editing a S4 methods needs particular attention as
by
> using showMethods("cenfit") and then
getMethod("cenfit"); in fact, I?ve been
> trying that but without much success (i.e. understanding of the cumbersome
> output)
>
> can anyone give me some help on how is probably better to proceed in order
> to get my new result?
>
> different alternative solutions or hints or advices are also more than
> welcomed
> (I?m pretty new on R and specially on the field of function handling and
> customizing)
>
> all the best
>
> max
>
>
>
--
Sarah Goslee
http://www.functionaldiversity.org
sorry sarah
you are right, my fault, this is the correct reproducible example
(a misinterpretation of LR type occurred in previous reproducible example)
my.ex<-structure(list(TEC = c(0.21, 0.077, 0.06, 0.033, 0.014, 0.0072
), LR = c(FALSE, FALSE, TRUE, FALSE, TRUE, FALSE)), .Names = c("TEC",
"LR"), row.names = c(NA, -6L), class = "data.frame")
but, nevertheless, still some problems exists because...
str(my.ex)
library(NADA)
with(my.ex,
cenfit(TEC,LR)
)
mycenfit <- function(x, y) {
result <- cenfit(x, y)
c(result, sum = result$n * result$mean)
}
with(my.ex,
mycenfit(TEC,LR)
)
giving me the following error message
Error in result$n : $ operator not defined for this S4 class
again pointing to the peculiar structure of S4 class (at least I think to
understand)
thank you for your reply
max
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