Hello,
Richard's idea is good but shouldn't it be `[.myclass` instead?
`[.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
}
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,
Rui Barradas
Às 03:13 de 20/10/19, Rolf Turner escreveu:
On 20/10/19 3:00 PM, Richard M. Heiberger wrote:
Look at
methods(as.data.frame)
Define your specialized columns to have a newly defined class, say
"myclass".
Then write as.data.frame.myclass
It will be similar to the function you already have in the lapply
statement.
Now your statement
X <- X[ok,]
should work.
Yes. That idea does indeed look promising. I'll check it out.
Thanks.
cheers,
Rolf
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