Hello,
Sorry, you're right, in the method it's x, X is the test dataframe.
Repost:
`[.myclass` <- function(x, i, j, drop = if (missing(i)) TRUE else
length(cols) == 1){
SaveAt <- lapply(x, attributes)
x <- NextMethod()
lX <- lapply(names(x),function(nm, x, Sat){
attributes(x[[nm]]) <- Sat[[nm]]
x[[nm]]}, x = x, Sat = SaveAt)
names(lX) <- names(x)
x <- as.data.frame(lX)
x
}
The (frequent) error comes from tests where a X was created in the
globalenv and found by the method.
Rui Barradas
Às 22:55 de 20/10/19, Rolf Turner escreveu:
On 21/10/19 1:15 AM, Rui Barradas wrote:
Hello,
Richard's idea is good but shouldn't it be `[.myclass` instead?
Yes, I kind of thought that, and cobbled together something on that
basis that seemed to work. However my code was rather a hodge-podge. I
kept having to work around errors that I didn't understand.
You seem to have a much clearer understanding of what's going on, and
your code is much cleaner than what I came up with.
`[.myclass` <- function(x, i, j, drop = if (missing(i)) TRUE else
length(cols) == 1){
SaveAt <- lapply(X, attributes)
X <- NextMethod()
lX <- lapply(names(X),function(nm, x, Sat){
attributes(x[[nm]]) <- Sat[[nm]]
x[[nm]]}, x = X, Sat = SaveAt)
names(lX) <- names(X)
X <- as.data.frame(lX)
X
}
But in the foregoing there seems to me to be some inconsistency in the
use of "X" and "x".
Should not the first function argument be "X" rather than "x"? Or
perhaps the "X" symbols in the code should be replaced by "x"? As in:
SaveAt <- lapply(x, attributes)
x <- NextMethod()
....
....
Or am I misunderstanding what's going on (as is so often
the case! :-( )?
X <- data.frame(a = letters[1:5], x = 1:5)
class(X) <- c("myclass", class(X))
attr(X$a, "attr_a1") <- "first_a"
attr(X$a, "attr_a2") <- "second_a"
str(X)
ok <- c(1, 3, 4)
X <- X[ok, ]
str(X)
Hope this helps,
Quite a lot! But I'd appreciate clarification w.r.t. the misgiving that
I expressed above.
Thanks.
cheers,
Rolf
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