On Tue, 24 Apr 2007, Tomas Mikoviny wrote:
> Hi everybody,
>
> I work with data with following pattern
>
> > comm
>
> "Date" "Value"
> 1 4/10/2007 361.2
> 2 4/11/2007 370.1
> 3 4/12/2007 357.2
> 4 4/13/2007 362.3
> 5 4/16/2007 363.5
> 6 4/17/2007 368.7
> 7 4/18/2007 354.7
> 8 4/19/2007 368.8
> 9 4/20/2007 367.1
> 10 ... ...
>
> and trying to convert it to time series using:
>
> > t=strptime(comm[1,1],"%m/%d/%Y")
> > x=ts(comm, start=as.POSIXct(t))
>
> Error in Math.difftime((end - start) * frequency + 1.01) :
> floornot defined for "difftime" objects
>
> Definitely I do something wrong but I can't find what is it!
At least things:
- ts() can only work with numeric time stamps (not POSIXct)
- you try to create a regular series (although your data is
not: there is not an observation on each day)
I would recommend to create a "zoo" series with "Date" index:
R> library("zoo")
R> z <- zoo(comm[,2], as.Date(strptime(comm[,1], "%m/%d/%Y")))
R> z
2007-04-10 2007-04-11 2007-04-12 2007-04-13 2007-04-16 2007-04-17
361.2 370.1 357.2 362.3 363.5 368.7
2007-04-18 2007-04-19 2007-04-20
354.7 368.8 367.1
hth,
Z
> Can anyone help me with this?
>
> Thanks.
>
> Tomas
>
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> 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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