Hello,
Using Arun's data example, instead of creating a factor "convert" to 4
digits years.
set.seed(1)
dat1 <- data.frame(Tahun=rep(c(98:99,00),each=36),
Bahun=rep(rep(1:12,times=3),each=3),
x=sample(1:500,108,replace=TRUE))
dat2 <- dat1 # operate on a copy
dat2$Tahun <- with(dat2, ifelse(Tahun < 71, 2000 + Tahun, 1900 + Tahun))
agg_dt1 <- aggregate(x=dat2[,3],by=dat2[,c(1,2)],FUN=sum)
head(agg_dt1)
Hope this helps,
Rui Barradas
Em 06-10-2012 03:38, arun escreveu:
Hi,
I hope this helps you.
I created a small dataset: 3 replications per month for 1998:2000.
set.seed(1)
dat1<-data.frame(Tahun=rep(c(98:99,00),each=36),Bahun=rep(rep(1:12,times=3),each=3),
x=sample(1:500,108,replace=TRUE))
dat2<-within(dat1,{Tahun<-factor(Tahun,levels=c(98,99,0))})
agg_dt1<-aggregate(x=dat2[,3],by=dat2[,c(1,2)],FUN=sum)
head(agg_dt1)
# Tahun Bahun x
#1 98 1 1252
#2 99 1 680
#3 0 1 687
#4 98 2 761
#5 99 2 860
#6 0 2 786
I guess this is what you wanted.
In addition, you can also use ddply() with a different way of grouping: but
with the same result.
library(plyr)
dd_dt1<-ddply(dat2,.(Tahun,Bahun),summarize, sum(x))
head(dd_dt1)
# Tahun Bahun ..1
#1 98 1 1252
#2 98 2 761
#3 98 3 440
#4 98 4 597
#5 98 5 987
#6 98 6 692
tail(dd_dt1)
# Tahun Bahun ..1
#31 0 7 685
#32 0 8 504
#33 0 9 633
#34 0 10 553
#35 0 11 914
#36 0 12 1039
A.K.
----- Original Message -----
From: Roslina Zakaria <zrosl...@yahoo.com>
To: "r-help@r-project.org" <r-help@r-project.org>
Cc:
Sent: Friday, October 5, 2012 8:09 PM
Subject: [R] arrange data
Dear r-users,
I have dailly rainfall data from year 1971 to 2000. I use aggregate to form
monthly rainfall data. What I don't understand is that the data for the year
2000 become on the top, instead of year 1971. Here are some codes and output:
agg_dt1 <- aggregate(x=dt1[,4],by=dt1[,c(1,2)],FUN=sum)
head(agg_dt1,20); tail(agg_dt1,20)
Tahun Bulan x
1 0 1 398.6
2 71 1 934.9
3 72 1 107.2
4 73 1 236.4
5 74 1 10.5
6 75 1 744.6
7 76 1 9.2
8 77 1 108.7
9 78 1 251.5
10 79 1 197.3
11 80 1 144.1
12 81 1 104.5
13 82 1 17.7
14 83 1 151.8
...
Thank you so much for your help.
Roslina
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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.
