Need help on dataframe

HI,
Sorry, there was a mistake, which I noticed after seeing David's post.
dat1<-read.table(text="
ID? V1? V2? V3? V4
1??? 6??? 5??? 3??? 2
2??? 3??? 2??? 2??? 1
3??? 6??? 5??? 3??? 2
4??? 12? 15? 3??? 2
5??? 6??? 8??? 3??? 2
6??? 3??? 2??? 4??? 1
7??? 6??? 5??? 3??? 3
8??? 12? 15? 3??? 1
9??? 6??? 5??? 3??? 3
10??? 3??? 2??? 7??? 5
11??? 6??? 5??? 8??? 2
12??? 12? 19? 3??? 2
13??? 6??? 5??? 3??? 2
14??? 3??? 4??? 2??? 1
15??? 6??? 5??? 6??? 2
16??? 12? 15? 5??? 2
17??? 6??? 5??? 5??? 2
18??? 3??? 2??? 8??? 1
19??? 6??? 5??? 3??? 9
20??? 12? 15? 3??? 10
21??? 6??? 5??? 3??? 2
22??? 3??? 2??? 2??? 11
23??? 6??? 5??? 3??? 4
24??? 12? 15? 9??? 2
25??? 6??? 5??? 3??? 2
26??? 3??? 2??? 2??? 1
27?? 6??? 5??? 3??? 2
28??? 12? 15? 3??? 2
29??? 6??? 8??? 3??? 2
30??? 3??? 2??? 4??? 1
31??? 6??? 5??? 3??? 3
32??? 12? 15? 3??? 1
33??? 6??? 5??? 3??? 3
34??? 3??? 2??? 7??? 5
35??? 6??? 5??? 8??? 2
36??? 12? 19? 3??? 2
37??? 6??? 5??? 3??? 2
38??? 3??? 4??? 2??? 1
",sep="",header=TRUE,stringsAsFactors=FALSE)
res<-aggregate(.~(1:nrow(dat1)-1)%/%12,data=dat1[,-1],mean)
? names(res)[1]<-"group"
A.K.

----- Original Message -----
From: Simonas Kecorius <simolas2008 at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Saturday, January 5, 2013 8:33 AM
Subject: [R] Need help on dataframe

Dear R users, I came up to a problem by taking means (or other summary
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 to
get:

V1? ? ? ? ? ? ? ? ? ? ? ? ? ? ? V2? ? ? ? ? ? ? ? V3? ? ? ? ? ? ? ?  V4
........................... 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 all the
dataframe at once and get a result as matrix?

Thank you in advance!

Need help on dataframe

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