R help - Mar 2011 - mean of runoff for several years

Hello everyone
I have a dataframe with 4 colums (year, month, day, runoff) for 1993-2009.
Now I like to calculate the average runoff for each day. Finally I like to
plot the median runoff for all this years. 
I tried with some loops, but it didn't work. Do you have any Tips for my
problem?
Any help is greatly appreciated! Thank you very much.
Dominique



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Tena koe Dominique

?tapply
?aggregate

For example,

dayMn <- tapply(yourData$runoff,
yourData[,c('year','month','day')], mean, na.rm=TRUE)
yearMed <- tapply(dayMn$runoff, dayMn$year, median, na.rm=TRUE)
with(yearMed, plot(year, runoff))

I have not tested the above and since I can never remember exact syntax or
output I would not be surprised if the above needed tweaking.

HTH ....

Peter Alspach

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of dominique
> Sent: Thursday, 24 March 2011 9:14 a.m.
> To: r-help at r-project.org
> Subject: [R] mean of runoff for several years
> 
> Hello everyone
> I have a dataframe with 4 colums (year, month, day, runoff) for 1993-
> 2009.
> Now I like to calculate the average runoff for each day. Finally I like
> to
> plot the median runoff for all this years.
> I tried with some loops, but it didn't work. Do you have any Tips for
> my
> problem?
> Any help is greatly appreciated! Thank you very much.
> Dominique
> 
> 
> 
> --
> View this message in context: http://r.789695.n4.nabble.com/mean-of-
> runoff-for-several-years-tp3400541p3400541.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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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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Dominique,

Let's call your dataframe, df.

Then try:

with(df, boxplot(runoff ~ month))

which will plot the daily runoff distribution by month.

Clint

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On Wed, 23 Mar 2011, dominique wrote:
> Hello everyone
> I have a dataframe with 4 colums (year, month, day, runoff) for 1993-2009.
> Now I like to calculate the average runoff for each day. Finally I like to
> plot the median runoff for all this years.
> I tried with some loops, but it didn't work. Do you have any Tips for
my
> problem?
> Any help is greatly appreciated! Thank you very much.
> Dominique
>
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/mean-of-runoff-for-several-years-tp3400541p3400541.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.
>