How to extract elements from vector in reverse order?

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of hp wan
Sent: Thursday, January 24, 2013 4:23 PM
To: r-help at r-project.org
Subject: [R] How to extract elements from vector in reverse order?

Hi all mailing listers,

I wanna get the last several elments of vector.
 e.g.  x <- c(1,2,3,.....,78, 79, 80)

How can I implement to assign last three elements to y,  y <- c(78, 79,
80)
?

In Matlab, It can easily achieve by y=x(end-2:end)


Thanks

Huaping Wan

You can get what you want in much the same way

y <- x[(length(x)-2):length(x)]


Hope this is helpful,

Dan

Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204

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Hi all mailing listers,

I wanna get the last several elments of vector.
e.g.  x <- c(1,2,3,.....,78, 79, 80)

How can I implement to assign last three elements to y,  y <- c(78, 79, 80)
?

?tail

In Matlab, It can easily achieve by y=x(end-2:end)

y <- tail(x, 3)

David Winsemius
Alameda, CA, USA

Hi,
?x<-1:80
y<- x[-(1:77)]
y

#[1] 78 79 80
#or 

?tail() #already suggested

If you want only the last element,,
library(pastecs)
last(x)
#[1] 80
A.K.




----- Original Message -----
From: hp wan <huaping.wan at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Thursday, January 24, 2013 7:23 PM
Subject: [R] How to extract elements from vector in reverse order?

Hi all mailing listers,

I wanna get the last several elments of vector.
e.g.? x <- c(1,2,3,.....,78, 79, 80)

How can I implement to assign last three elements to y,? y <- c(78, 79, 80)
?

In Matlab, It can easily achieve by y=x(end-2:end)


Thanks

Huaping Wan

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