-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of John Kane
Sent: Saturday, January 05, 2013 11:23 AM
To: Simonas Kecorius; r-help at r-project.org
Subject: Re: [R] Need help on dataframe
Well, a rather simple-minded, brute force approach would be to add a
factor variable to the data frame and use aggregate on it.
I am sure there are better ways but this will work.
EXAMPLE
###
xx <- data.frame(aa =1:24,
b = matrix(sample(c(1,2,3,4,5,6), 72, replace =
TRUE), nrow= 24))
dd <-rep(c("a","b"), each= 12)
xx <- cbind(dd, xx)
aggregate(xx[,3:5], list(xx$dd), mean)
################
By the way, when supplying data samples a good way is to use the dput
command. Try ?dput for information
John Kane
Kingston ON Canada
-----Original Message-----
From: simolas2008 at gmail.com
Sent: Sat, 5 Jan 2013 15:33:03 +0200
To: r-help at r-project.org
Subject: [R] Need help on dataframe
Dear R users, I came up to a problem by taking means (or other
statistics) of a big dataframe.
Suppose we do have a dataframe:
ID V1 V2 V3 V4 ........................ V71
1 6 5 3 2 ........................ 3
2 3 2 2 1 ........................ 1
3 6 5 3 2 ........................ 3
4 12 15 3 2 ........................ 100
........................................................
........................................................
288 10 20 30 30 .......................... 499
I need to find out the way, how to calculate a mean of every 12 lines
........................... V71
mean from 1 to 7 same as V1 same as V1
mean from 8 to 14 same as V1 same as V1
etc.
I can do it column by column using:
y.ts <- ts(y$V1, frequency=12)
aggregate(y.ts, FUN=mean)
Bu this is a hardcore... Can anyone suggest a better way to compute
the
dataframe at once and get a result as matrix?
Thank you in advance!
--
Simonas Kecorius
**
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