[R] combine two columns into one

[arun]

Hi,
May be I misunderstood your question:
dat<- read.table(text="
Date    Time  Var
1            1        2
1          1        4
1          1        5
1          2          8
1          2          8
1        2          9
2        1            3
2        1              4
2        1            4
",sep="",header=TRUE)
dat$UniqueID <- paste(dat$Date,dat$Time, sep = '_')
 aggregate(dat$Var,list(dat$UniqueID),sum) #isn't this the correct order
#  Group.1  x
#1     1_1 11
#2     1_2 25
#3     2_1 11
library(plyr)
ddply(dat,.(UniqueID),summarize,Var=sum(Var))
#  UniqueID Var
#1      1_1  11
#2      1_2  25
#3      2_1  11
A.K.



----- Original Message -----
From: Ye Lin <yelin at lbl.gov>
To: R help <r-help at r-project.org>
Cc: 
Sent: Wednesday, May 29, 2013 2:23 PM
Subject: [R] combine two columns into one

Hey all!

I have a time series dataset like this:

Date    Time   Var
1            1        2
1           1        4
1           1         5
1          2          8
1          2          8
1         2           9
2        1            3
2        1              4
2        1            4

I created a unique id for each row:
dat$UniqueID <- paste(dat$Date,dat$Time, sep = '_')

then

aggregate(dat$Var, list(dat$UniqueID), sum)

however the final output is not in ideal order I look for (I simply this
example provided above).I would like to have order like this:

1_1
1_2
2_1

Thanks for your help!

    [[alternative HTML version deleted]]

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