[R] Time problems (POSIXct)

[Research]

Thanks Gabor,

I suppose that in the example below,  you can convet Date to POSIXct as 
well, can't you?

Best,
Costas


On 20/05/2010 18:08, Gabor Grothendieck wrote:
> 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)
>>      
>>>        
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
>>
>>      
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