[R] empty data frame and POSIXct data types

[Olivier Crouzet]

Hi Stefano,

my guess is that you're expecting data recycling to apply but your
data frame is only one row long... therefore you can't insert a 2-row
vector into a 1-row vector. Recycling won't help.

You should specify the number of rows that will be required in your
data frame using (e.g) rep().

(here I use 10 rows as an example)

mydf <- data.frame(data_POSIX=rep(as.POSIXct(NA), 10),
value=as.numeric(NA)) 

Olivier.

On Thu, 24 Jun 2021 13:34:31
+0000 Stefano Sofia <stefano.sofia using regione.marche.it> wrote:

> Dear R users,
> I know that this question is silly (I am not a R newby) but I already
> wasted quite a lot of energies trying to fill in an empty data frame
> (with "POSIXct" "POSIXt" data type).
> 
> Suppose I create
> mydf <- data.frame(data_POSIX=as.POSIXct(NA), value=as.numeric(NA))
> day1 <- as.POSIXct("2018-02-01-00-00", format="%Y-%m-%d-%H-%M",
> tz="Etc/GMT-1") day2 <- as.POSIXct("2018-02-02-00-00",
> format="%Y-%m-%d-%H-%M", tz="Etc/GMT-1")
> 
> then
> mydf$data_POSIX <- c(day1, day2)
> 
> does not work, it gives me:
> "Error in `$<-.data.frame`(`*tmp*`, data_POSIX, value = c(1517439600,
> 1517612400 : replacement has 2 rows, data has 1"
> 
> There are few basic concepts that I am missing.
> Why c(day1, day2) is not a vector?
> Why I am not able to populate my data frame?
> 
> Could somebody please give me the right hints?
> Thank you for your precious help
> Stefano
> 
> 
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-- 
  Olivier Crouzet, PhD
  http://olivier.ghostinthemachine.space
  /Maître de Conférences/
  @LLING - Laboratoire de Linguistique de Nantes
    UMR6310 CNRS / Université de Nantes