[R] Notation for previous observation in a data frame

[arun]

Hi,

Try this:  


 dat1<-data.frame(var1=15:25)
dat1$var2<-NA
 dat1$var2[2:11]<-dat1$var1[1:10]
 dat1
   var1 var2
1    15   NA
2    16   15
3    17   16
4    18   17
5    19   18
6    20   19
7    21   20
8    22   21
9    23   22
10   24   23
11   25   24

You can also do the same within the single variable.
e.g. dat1$var1[6:10]<-dat1$var[5:9]



A.K.



----- Original Message -----
From: Ernie Tedeschi <ernie.tedeschi at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Saturday, July 7, 2012 11:20 PM
Subject: [R] Notation for previous observation in a data frame

I've created a data frame in R, but in order to clean up some of the data,
I need to set certain variable observations equal to the value of their
previous observation (it would be conditional, but that part's less
important right now). In Stata, I would simply set var = var[_n-1] in those
cases. What is the R equivalent?

    [[alternative HTML version deleted]]

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