On 11/12/2010 9:57 AM, Alexander Senger wrote:
Hello list,
here is what I stumbled upon:
1> test<- data.frame(time=as.POSIXct((1:2),origin="2000-1-1"))
1> test
time
1 2000-01-01 00:00:01
2 2000-01-01 00:00:02
1> rbind(test,b=1:2)
Fehler in as.POSIXct.numeric(value) : 'origin' muss angegeben werden
When I try to attach an additional row to a dataframe with a row
containing dates I get the error shown above (which says that there was
an error in "as.POSIXct.numeric(value)": an 'origin' has to be given).
I haven't found any information on this so I would like to know whether
this is to be regarded as a bug and be properly reported.
I do not think it is a bug; I think you may be expecting too much out of
rbind(). rbind() [well, in this case, rbind.data.frame] will bind the
rows of two data frame together, assuming they have the same column
structure. You are passing a numeric vector as the second argument,
expecting it to be cast into a date and put into a data frame before
binding.
The POSIXct class does not keep information about an origin used to
convert a number into a date, so subsequent attempts to convert need the
origin supplied (the direct error you are getting). However, that is
not enough; you still need to cast the vector into a data frame with the
right column name:
rbind(test, data.frame(time=as.POSIXct(1:2, origin="2000-01-01")))
# time
#1 2000-01-01 00:00:01
#2 2000-01-01 00:00:02
#3 2000-01-01 00:00:01
#4 2000-01-01 00:00:02
Another though, do you really mean to add rows? Or did you want to add
another column?
cbind(test,b=1:2)
# time b
#1 2000-01-01 00:00:01 1
#2 2000-01-01 00:00:02 2
This is my sessionInfo:
1> sessionInfo()
R version 2.10.1 (2009-12-14)
i486-pc-linux-gnu
locale:
[1] LC_CTYPE=de_DE.utf8 LC_NUMERIC=C
[3] LC_TIME=de_DE.utf8 LC_COLLATE=de_DE.utf8
[5] LC_MONETARY=C LC_MESSAGES=de_DE.utf8
[7] LC_PAPER=de_DE.utf8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=de_DE.utf8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] tools_2.10.1
I'm aware that my version is somewhat outdated but it seems not much has
changed with rbind() since then. Please correct me if I'm wrong.
I don't know how much has; I ran these examples with
R version 2.12.0 Patched (2010-11-04 r53526)
Platform: i386-pc-mingw32/i386 (32-bit)
Thank you for your attention
Alex
--
Brian S. Diggs, PhD
Senior Research Associate, Department of Surgery
Oregon Health & Science University
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