[R] Help with data containing date

[Gabor Grothendieck]

Just one other addition.  If by monthly summary you mean a summary
that has an entry for each year/month combo rather than just one
entry for all Januaries, one entry for all Februaries etc. then try this
which works in both the Date and chron cases:

aggregate(z, as.yearmon, mean)


On Tue, Sep 8, 2009 at 11:36 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> Try this:
>
> Lines <- "Date             A    B        C       D           E
>  1978-10-22   18  20.64   0.0   0.176     -1.76
>  1978-10-23   15  17.06   0.4   0.147      2.52
>  1978-10-24    3   7.588   0.0   0.068     -6.86
>  1978-10-25    9  11.491   0.0   0.102    -1.01
>  1978-10-26   13  14.98   1.4    0.130     1.26 "
>
> library(zoo); library(chron)
> z <- read.zoo(textConnection(Lines), header = TRUE, FUN = as.chron)
> aggregate(z, months, mean)
> aggregate(z, years, mean)
>
> chron was used above to take advantage of the convenient months()
> and years() functions that are available for it although it could be
> done using Date class with only slightly more complexity:
>
> library(zoo)
> z <- read.zoo(textConnection(Lines), header = TRUE)
> aggregate(z, format(time(z), "%m"), mean)
> aggregate(z, format(time(z), "%Y"), mean)
>
> Read the three zoo vignettes and the article on dates in R News 4/1 as well
> as the references to that article.
>
> On Tue, Sep 8, 2009 at 11:23 PM, Subodh Acharya<shoebodh at gmail.com> wrote:
>> Hello Everyone,I think this is a very simple problem, I have been struggling
>> with it for a few days now.
>> I have a 10-year daily data  in the following format.
>>
>>
>>  Date             A    B        C       D           E
>>  1978-10-22   18  20.64   0.0   0.176     -1.76
>>  1978-10-23   15  17.06   0.4   0.147      2.52
>>  1978-10-24    3   7.588   0.0   0.068     -6.86
>>  1978-10-25    9  11.491   0.0   0.102    -1.01
>>  1978-10-26   13  14.98   1.4    0.130     1.26
>>
>> I want to calculate the monthly and Annual average averages of A, B, C, D,
>> and E, for the 10 years.
>>
>> I tried to use the xts package to convert the data into a time series object
>> but was not able to even change it into the time series object.
>> Any help would be highly appreciated
>>
>> Thank you in advance.
>>
>> --
>> Subodh Acharya
>> University of Florida
>> Gainesville, FL.
>>
>>        [[alternative HTML version deleted]]
>>
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>>
>