[R] add identifier column by row

[arun]

May be this helps:

dat<- read.table(text="
ID      Var
1          1
2          4
3        6
4        7
5          7
6          8
7       9     
",sep="",header=TRUE)
 dat$Date<-cumsum(seq_len(nrow(dat))%%2)
 dat
#  ID Var Date
#1  1   1    1
#2  2   4    1
#3  3   6    2
#4  4   7    2
#5  5   7    3
#6  6   8    3
#7  7   9    4
A.K.


----- Original Message -----
From: Ye Lin <yelin at lbl.gov>
To: R help <r-help at r-project.org>
Cc: 
Sent: Tuesday, May 21, 2013 4:16 PM
Subject: [R] add identifier column by row

I want to add identifier column (Date) to a time series data frame. I want
to name the "Date" column be from 1 to 30 every 1440 rows.

Say I have a data like this (I simply my actual data here):

$dat

ID       Var
1          1
2          4
3         6
4         7
5          7
6          8

How can I add identifier column (Date) from 1 to 3 every 2 rows and have
output like this:

ID       Var  Date
1          1      1
2          4     1
3         6      2
4         7      2
5          7     3
6          8      3

Thanks,

    [[alternative HTML version deleted]]

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