[R] Problems merging with POSIXct objects and all = TRUE
maechler at stat.math.ethz.ch
Mon Oct 15 11:39:24 CEST 2001
>>>>> "David" == "David Kane <David Kane" <a296180 at mica.fmr.com> writes:
David> I am having problems using merge with all = TRUE when one of the
David> dataframes has objects of class POSIXct. If this is a bug, let
David> me know and I will report it to r-bugs. Here is an example:
... (R version 1.3.0)
> x <- data.frame(a = as.POSIXct(Sys.time() + (1:3)*10000), b = LETTERS[1:3])
1 2001-10-04 17:37:46 A
2 2001-10-04 20:24:26 B
3 2001-10-04 23:11:06 C
> y <- data.frame(b = LETTERS[3:4], c = 1:2)
1 C 1
2 D 2
> merge(x, y)
b a c
1 C 2001-10-04 23:11:06 1 # This answer is correct
> merge(x, y, all = TRUE)
Error in as.POSIXct.default(value) : Don't know how to convert `value' to class "POSIXct"
The reason is that merge(x,y, all = TRUE) fills in NAs at "appropriate"
places, and currently, it seems we have no (automatic) NA concept for
Error in as.POSIXlt(NA) : Don't know how to convert `NA' to class "POSIXlt"
Error in as.POSIXct.default(NA) : Don't know how to convert `NA' to class "POSIXct"
Error in fromchar(x) : character string is not in a standard unambiguous format
This might be considered a bug although only in a loose sense of the word.
Martin Maechler <maechler at stat.math.ethz.ch> http://stat.ethz.ch/~maechler/
Seminar fuer Statistik, ETH-Zentrum LEO D10 Leonhardstr. 27
ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
phone: x-41-1-632-3408 fax: ...-1228 <><
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