Hi,
Many apologies for the simplicity (hopefully!) of this request - I can't
find it on the forum, but it may have been asked in the past.
I have a data frame consisting of ~2000 rows. I simply want to take the
average of the first 6, then the next 6, then the next 6 until the end of
the table.
The command
mean(mole[1:6,c("PercentPI")])
gets me the first 6 rows (column is PercentPI), but I don't know how to
increase the rows incrementally.
Thanks in advance.
J
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What about something like this:
tmp <- data.frame(var1 = rnorm(36), ind = gl(6,6))
with(tmp, tapply(var1, ind, mean))
You can see that your version of
mean(tmp[1:6,c("var1")])
gives the same as mine for the first 6 rows.
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of jsf1982
Sent: Tuesday, August 13, 2013 12:46 PM
To: r-help at r-project.org
Subject: [R] Regular repeats
Hi,
Many apologies for the simplicity (hopefully!) of this request - I can't
find it on the forum, but it may have been asked in the past.
I have a data frame consisting of ~2000 rows. I simply want to take the average
of the first 6, then the next 6, then the next 6 until the end of the table.
The command
mean(mole[1:6,c("PercentPI")])
gets me the first 6 rows (column is PercentPI), but I don't know how to
increase the rows incrementally.
Thanks in advance.
J
--
View this message in context:
http://r.789695.n4.nabble.com/Regular-repeats-tp4673653.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.
On 13-08-2013, at 18:46, jsf1982 <jamie.freeman at ucl.ac.uk> wrote:> Hi, > Many apologies for the simplicity (hopefully!) of this request - I can't > find it on the forum, but it may have been asked in the past. > > I have a data frame consisting of ~2000 rows. I simply want to take the > average of the first 6, then the next 6, then the next 6 until the end of > the table. > The command > > mean(mole[1:6,c("PercentPI")]) > > gets me the first 6 rows (column is PercentPI), but I don't know how to > increase the rows incrementally.Something like this N <- 27 dd <- data.frame(A=rnorm(1:N),index=gl(6,6,N)) aggregate(dd$A,by=list(dd$index),mean) Berend
Hi,
You could try:
set.seed(24)
? dat1<- as.data.frame(matrix(sample(1:50,29*6,replace=TRUE),ncol=6))
((seq_len(nrow(dat1))-1)%/%6)+1
# [1] 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5
#For a particular column:
aggregate(dat1[,5],list(((seq_len(nrow(dat1))-1)%/%6)+1),FUN=mean)
#? Group.1??????? x
#1?????? 1 38.16667
#2?????? 2 29.50000
#3?????? 3 23.16667
#4?????? 4 21.16667
#5?????? 5 20.60000
#or for the whole columns
aggregate(dat1,list(((seq_len(nrow(dat1))-1)%/%6)+1),FUN=mean)
#? Group.1?????? V1?????? V2?????? V3?????? V4?????? V5?????? V6
#1?????? 1 28.33333 17.50000 12.66667 35.00000 38.16667 30.16667
#2?????? 2 26.16667 31.33333 35.33333 19.66667 29.50000 24.83333
#3?????? 3 24.00000 11.83333 20.00000 25.50000 23.16667 20.83333
#4?????? 4 18.33333 23.33333 23.66667 20.33333 21.16667 21.16667
#5?????? 5 22.60000 30.40000 17.40000 21.80000 20.60000 24.40000
#or
library(plyr)
res1<-ddply(dat1,.(((seq_len(nrow(dat1))-1)%/%6)+1),summarize,MeanV1=mean(V1))
?colnames(res1)[1]<-"Group"
res1
#? Group?? MeanV1
#1???? 1 28.33333
#2???? 2 26.16667
#3???? 3 24.00000
#4???? 4 18.33333
#5???? 5 22.60000
A.K.
----- Original Message -----
From: jsf1982 <jamie.freeman at ucl.ac.uk>
To: r-help at r-project.org
Cc:
Sent: Tuesday, August 13, 2013 12:46 PM
Subject: [R] Regular repeats
Hi,
Many apologies for the simplicity (hopefully!) of this request - I can't
find it on the forum, but it may have been asked in the past.
I have a data frame consisting of ~2000 rows. I simply want to take the
average of the first 6, then the next 6, then the next 6 until the end of
the table.
The command
mean(mole[1:6,c("PercentPI")])
gets me the first 6 rows (column is PercentPI), but I don't know how to
increase the rows incrementally.
Thanks in advance.
J
--
View this message in context:
http://r.789695.n4.nabble.com/Regular-repeats-tp4673653.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.