[R] fill 0-row data.frame with 1 line of NAs
Rui Barradas
ruipbarradas at sapo.pt
Tue Jul 10 15:57:37 CEST 2012
Hello,
If you write a function, it becomes less convoluted...
empty <- function(x){
if(NROW(x) == 0){
y <- rep(NA, NCOL(x))
names(y) <- names(x)
y
}else x
}
(.xb <- iris[ iris$Species=='zz', ])
empty(.xb)
Hope this helps,
Rui Barradas
Em 10-07-2012 14:15, Liviu Andronic escreveu:
> Dear all
> Is there a simpler method to achieve the following: When I obtain an
> empty data.frame after subsetting, I need for it to contain one line
> of NAs. Here's a dummy example:
>> (.xb <- iris[ iris$Species=='zz', ])
> [1] Sepal.Length Sepal.Width Petal.Length Petal.Width Species
> <0 rows> (or 0-length row.names)
>> dim(.xb)
> [1] 0 5
>> (.xa <- data.frame(matrix(rep(NA, ncol(.xb)), 1)))
> X1 X2 X3 X4 X5
> 1 NA NA NA NA NA
>> names(.xa) <- names(.xb)
>> (.xb <- .xa)
> Sepal.Length Sepal.Width Petal.Length Petal.Width Species
> 1 NA NA NA NA NA
>
>
> The solution I came up with is way too convoluted. Anything simpler? Regards
> Liviu
>
>
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