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Georg Hoermann

2005-Feb-10 10:01 UTC

[R] Annual cumulative sums from time series

Hello world,

I am actually transferring a course in data management for
students in biology, geography and agriculture 
from statistica to R - it works
surprisingly well. If anyone is interested in my scratch/notepad
(in German language), please see

www.hydrology.uni-kiel.de/~schorsch/statistik/statistik_datenauswertung.pdf

(pages 40-52)

The dataset is:

www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv

It contains a 10 year dataset. So far for introduction, now
comes the problem:

we often need cumulative *annual* sums (sunshine, precipitation),
 i.e. the sum
must reset to 0 at the beginning of the year. I know
of cumsum(), but I do not now how to split the dataset automagically 
into annual pieces so I can cumsum() every year separately.
I have the strong hope that the solution is one of these
one-liners which leave the students with eyes wide open in surprise and 
makes them true believers in the power of the command-line 8-).

Thanks & Greetings
Georg


-- 
Georg Hoermann, Luebeck, Germany
Tel. 0451/47 70 32, 0172/431 57 15, Penguin #189476

Dimitris Rizopoulos

2005-Feb-10 10:28 UTC

head link

[R] Annual cumulative sums from time series

maybe something like this:

dat <- data.frame(years=rep(1994:2004, each=10), x=rnorm(110), 
y=rnorm(110))
lapply(split(dat[,-1], dat$years), cumsum)

is what you want.

I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Georg Hoermann" <georg.hoermann at gmx.de>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, February 10, 2005 11:01 AM
Subject: [R] Annual cumulative sums from time series

> Hello world,
>
> I am actually transferring a course in data management for
> students in biology, geography and agriculture
> from statistica to R - it works
> surprisingly well. If anyone is interested in my scratch/notepad
> (in German language), please see
>
> www.hydrology.uni-kiel.de/~schorsch/statistik/statistik_datenauswertung.pdf
>
> (pages 40-52)
>
> The dataset is:
>
> www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv
>
> It contains a 10 year dataset. So far for introduction, now
> comes the problem:
>
> we often need cumulative *annual* sums (sunshine, precipitation),
> i.e. the sum
> must reset to 0 at the beginning of the year. I know
> of cumsum(), but I do not now how to split the dataset automagically
> into annual pieces so I can cumsum() every year separately.
> I have the strong hope that the solution is one of these
> one-liners which leave the students with eyes wide open in surprise 
> and
> makes them true believers in the power of the command-line 8-).
>
> Thanks & Greetings
> Georg
>
>
> -- 
> Georg Hoermann, Luebeck, Germany
> Tel. 0451/47 70 32, 0172/431 57 15, Penguin #189476
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
>

Petr Pikal

2005-Feb-10 10:37 UTC

head link

[R] Annual cumulative sums from time series

Hi Georg

If you know which value belongs to which year you can use

tapply, by, aggregate family like:

years<-rep(c(2000,2001,2002,2003), each=10)
values<-(1:40)
test<-cbind(years,values)
test<-data.frame(test)
aggregate(test$values,list(y=test$years),sum)

Cheers
Petr



On 10 Feb 2005 at 11:01, Georg Hoermann wrote:
> Hello world,
> 
> I am actually transferring a course in data management for
> students in biology, geography and agriculture 
> from statistica to R - it works
> surprisingly well. If anyone is interested in my scratch/notepad
> (in German language), please see
> 
> www.hydrology.uni-kiel.de/~schorsch/statistik/statistik_datenauswertun
> g.pdf
> 
> (pages 40-52)
> 
> The dataset is:
> 
> www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv
> 
> It contains a 10 year dataset. So far for introduction, now
> comes the problem:
> 
> we often need cumulative *annual* sums (sunshine, precipitation),
>  i.e. the sum
> must reset to 0 at the beginning of the year. I know
> of cumsum(), but I do not now how to split the dataset automagically
> into annual pieces so I can cumsum() every year separately. I have the
> strong hope that the solution is one of these one-liners which leave
> the students with eyes wide open in surprise and makes them true
> believers in the power of the command-line 8-).
> 
> Thanks & Greetings
> Georg
> 
> 
> -- 
> Georg Hoermann, Luebeck, Germany
> Tel. 0451/47 70 32, 0172/431 57 15, Penguin #189476
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
Petr Pikal
petr.pikal at precheza.cz

Roger Bivand

2005-Feb-10 11:02 UTC

head link

[R] Annual cumulative sums from time series

On Thu, 10 Feb 2005, Georg Hoermann wrote:
> Hello world,
> 
> I am actually transferring a course in data management for
> students in biology, geography and agriculture 
> from statistica to R - it works
> surprisingly well. If anyone is interested in my scratch/notepad
> (in German language), please see
> 
> www.hydrology.uni-kiel.de/~schorsch/statistik/statistik_datenauswertung.pdf
> 
> (pages 40-52)
> 
> The dataset is:
> 
> www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv
> 
> It contains a 10 year dataset. So far for introduction, now
> comes the problem:
> 
> we often need cumulative *annual* sums (sunshine, precipitation),
>  i.e. the sum
> must reset to 0 at the beginning of the year. I know
> of cumsum(), but I do not now how to split the dataset automagically 
> into annual pieces so I can cumsum() every year separately.
> I have the strong hope that the solution is one of these
> one-liners which leave the students with eyes wide open in surprise and 
> makes them true believers in the power of the command-line 8-).
> 
> kiel <-
read.csv(url("http://www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv"))
> yrs <- factor(strftime(strptime(as.character(kiel$DATUM),
"%d.%m.%Y"),+ "%Y")) # this is clumsy, there are probably better
ways> tpks1 <- unlist(tapply(kiel$Sonnen, yrs, cumsum))
> str(tpks1) Named num [1:3652] 0.12 0.24 0.24 0.24 5.52 ...
 - attr(*, "names")= chr [1:3652] "19891" "19892"
"19893" "19894" ...> kiel$Sonnen[1:5][1] 0.12 0.12 0.00 0.00 5.28

I don't know if you want the name attribute on your annual cumulative 
sums, but for now they help control what's going on. This looks OK:
> try1 <- tapply(kiel$Sonnen, yrs, cumsum)
> cols <- rainbow(length(try1))
> plot(x=c(1,366), y=c(0,1200), type="n")
> for (i in 1:length(try1)) lines(1:length(try1[[i]]), try1[[i]], 
+ col=cols[i])> legend(c(0,70), c(700,1100), names(try1), col=cols, lwd=1)
for a quick impression.

> Thanks & Greetings
> Georg
> 
> 
> 
-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no

Brahm, David

2005-Feb-10 16:20 UTC

head link

[R] Annual cumulative sums from time series

Georg Hoermann [mailto:georg.hoermann at gmx.de] wrote:> www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv ...
contains a 10 year dataset.> We often need cumulative *annual* sums (sunshine, precipitation), i.e.
the sum must reset to 0> at the beginning of the year. I know of cumsum(), but I do not now how
to split the dataset> automagically into annual pieces so I can cumsum() every yearseparately.

Several replies have been given using tapply/aggregate/split; here is a
more primitive approach.
I do the cumsum once for the series, and call it "x".  Then I subtract
from x the value of x on 12/31
of the prior year:

R> y <- read.csv("erle_stat.csv", as.is=TRUE)
R> year <- substring(y$DATUM, 7)
R> x <- cumsum(y$Peff)
R> y$cumPeff <- x - c(0,x)[match(year, year)]

-- David Brahm (brahm at alum.mit.edu)

Georg Hoermann

2005-Feb-10 20:26 UTC

head link

[R] Annual cumulative sums from time series - SOLVED + questions

Roger Bivand wrote:> On Thu, 10 Feb 2005, Georg Hoermann wrote:
> Hello world,

based on the code of Roger I have now two solutions:

the first one (one line for the whole dataset)
--------- cut here ------

erle <- 
read.csv(url("http://www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv"))
jahre <- factor(substring(erle$DATUM, 7))
tpks1 <- unlist(tapply(erle$Sonnen, jahre, cumsum))
plot(tpks1, type="l")

--------- cut here -------

The second one plots one line for each year:

---- start - cut here ----
# read data in from Internet
erle <- 
read.csv(url("http://www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv"))
# extract Year as a factor from variable DATUM
jahre <- factor(substring(erle$DATUM, 7))
try1 <- tapply(erle$Sonnen, jahre, cumsum)
# create colors for every year from rainbow color scheme
cols <- rainbow(length(try1))
plot(x=c(1,366), y=c(0,1200), type="n", xlab="Days",
ylab="Cumulative
sunshine (h)")
# draw the lines, one line for each year
for (i in 1:length(try1)) lines(1:length(try1[[i]]), try1[[i]], col=cols[i])

# ...and the legend
legend(c(0,100), c(400,1100), names(try1), col=cols, lwd=1, bty="n")

---- end cut here -----

For the second example, a mean sum for all years would also be a good 
idea...

Thanks for all solutions...

Merci & Gruss
Georg

-- 
Georg Hoermann, Dep. of Hydrology, Ecology, Kiel University, Germany
Tel. 0431-880-1207, icq - 348 340 729, 0172/4315715, Penguin #189476

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