Moving column averaging

I don't know the answer, but would suppose not.
You could test this for yourself using:
system.time()
example: 
system.time(rnorm(100000,0,1)) 

Chega wrote
This solved my problem - Thanks a lot for your help! Please allow me one
more question: Works zoo's rollapply on a plain matrix faster than on a
zoo object? I am asking since I wanted to apply the provided averaging
code to a larger matrix (2500 rows x 200 cols), which is quite time
consuming...

Thanks again!

Chega

________________________________
From: B77S [via R] &lt;ml-node+s789695n4143909h3 at .nabble&gt;
To: Chega &lt;chegaga@&gt; 
Sent: Friday, December 2, 2011 6:16 AM
Subject: Re: Moving column averaging

Sorry for that, and thanks Gabor, 
I could have sworn that it wouldn't. 

Gabor Grothendieck wrote
On Thu, Dec 1, 2011 at 7:13 PM, B77S <[hidden email]> wrote: 
# need zoo to use rollapply() 

# your data (I called df) 
df <- structure(list(a = 1:2, b = 2:3, c = c(5L, 9L), d = c(9L, 6L), 
? ?e = c(1L, 5L), f = c(4, 7)), .Names = c("a", "b", "c", "d", 
"e", "f"), class = "data.frame", row.names = c(NA, -2L)) 

# transpose and make a zoo object 
df2 <- zoo(t(df)) 

#rollapply to get means and transpose back 
means <- t(rollapply(df2, width=2, by=2, FUN=mean)) 

# adding the combined column names you requested 
colnames(means) <- apply(matrix(names(df), nrow=2), 2, paste,
collapse=", ") 

Note that zoo's rollapply also works on plain matrices and vectors. 

-- 
Statistics & Software Consulting 
GKX Group, GKX Associates Inc. 
tel: 1-877-GKX-GROUP 
email: ggrothendieck at gmail.com 

______________________________________________ 
[hidden email]?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. 

________________________________

If you reply to this email, your message will be added to the discussion
below:
http://r.789695.n4.nabble.com/Moving-column-averaging-tp4130179p4143909.html
To unsubscribe from Moving column averaging, click here.
NAML

--
View this message in context: http://r.789695.n4.nabble.com/Moving-column-averaging-tp4130179p4154770.html
Sent from the R help mailing list archive at Nabble.com.