[R] arrange data

[arun]

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 <zroslina at yahoo.com>
To: "r-help at r-project.org" <r-help at 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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