[R] Time problems (POSIXct)

[Gabor Grothendieck]

The warning message does tell you exactly what was wrong.   You are
trying to merge zoo objects that have two different index classes.
The first is "POSIXct" and the second is "Date" class.  Next time
please provide your data in reproducible form
as shown here:

> library(zoo)
> z1 <- zoo(1:6, as.Date(c("1950-01-05", "1950-01-06", "1950-01-09",
+   "1950-01-10", "1950-01-11", "1950-01-12")))
> z2 <- zoo(c(16.66, 16.85, 16.93, 16.98, 17.08, 17.03),
+ as.POSIXct(c("1950-01-03, GMT", "1950-01-04, GMT", "1950-01-05, GMT",
+   "1950-01-06, GMT", "1950-01-09 GMT", "1950-01-10 GMT")))
>
> merge(z1, z2 = aggregate(z2, as.Date, identity))
           z1    z2
1950-01-03 NA 16.66
1950-01-04 NA 16.85
1950-01-05  1 16.93
1950-01-06  2 16.98
1950-01-09  3 17.08
1950-01-10  4 17.03
1950-01-11  5    NA
1950-01-12  6    NA
>
>
> # or
> z2.Date <- z2
> time(z2.Date) <- as.Date(time(z2.Date))
>
> merge(z1, z2.Date)
           z1 z2.Date
1950-01-03 NA   16.66
1950-01-04 NA   16.85
1950-01-05  1   16.93
1950-01-06  2   16.98
1950-01-09  3   17.08
1950-01-10  4   17.03
1950-01-11  5      NA
1950-01-12  6      NA


On Thu, May 20, 2010 at 10:48 AM, Research <risk2009 at ath.forthnet.gr> wrote:
> Hello,
>
> I have a zoo time series object (say a)  with the following time
> stamp/format
>
>
>
> [1] "1950-01-03 GMT" "1950-01-04 GMT" "1950-01-05 GMT" "1950-01-06 GMT"
> [5] "1950-01-09 GMT" "1950-01-10 GMT"
>
>
> and another (say b) with
>
>
> [1] "1950-01-05" "1950-01-06" "1950-01-09" "1950-01-10" "1950-01-11"
> [6] "1950-01-12"
>
>
> I want to merge these series   but when I try:
>
>
>> head(merge(a, b ))
>                    a                   b
> 1950-01-03 02:00:00       16.66   NA
> 1950-01-04 02:00:00       16.85   NA
> 1950-01-05 02:00:00       16.93   NA
> 1950-01-06 02:00:00       16.98   NA
> 1950-01-09 02:00:00       17.08   NA
> 1950-01-10 02:00:00       17.03   NA
> Warning message:
> In merge.zoo(a, b) :
>  Index vectors are of different classes: POSIXt Date
>>
>
> Anybody can help?  I tried as.POSIXct(a,tz="GMT") but it doesn't seem to
> work....
>
> Many thanks in advance!
>
> Costas
>              _
> platform       i386-pc-mingw32
> arch           i386
> os             mingw32
> system         i386, mingw32
> status
> major          2
> minor          10.1
> year           2009
> month          12
> day            14
> svn rev        50720
> language       R
> version.string R version 2.10.1 (2009-12-14)
>>
>
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>