R help - Apr 2011 - Odd results with lag

Given a vector:
> S <- c(1,1,0,0,1,1,-1,-1,-1,0,1)
Then I expected lag(S) to give...

c(1,0,0,1,1,-1,-1,-1,0,1)

but instead...
> S
 [1]  1  1  0  0  1  1 -1 -1 -1  0  1
> lag(S)
 [1]  1  1  0  0  1  1 -1 -1 -1  0  1
attr(,"tsp")
[1]  0 10  1
>
This is very odd.  What is happening?

I get what I using S[-1] so I have no problem, but I obviously do not
understand some thing!

Worik

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On Thu, Apr 7, 2011 at 6:11 PM, Worik R <worikr at gmail.com>
wrote:
> Given a vector:
>
>> S <- c(1,1,0,0,1,1,-1,-1,-1,0,1)
>
> Then I expected lag(S) to give...
>
> c(1,0,0,1,1,-1,-1,-1,0,1)
>
> but instead...
>
>> S
> ?[1] ?1 ?1 ?0 ?0 ?1 ?1 -1 -1 -1 ?0 ?1
>> lag(S)
> ?[1] ?1 ?1 ?0 ?0 ?1 ?1 -1 -1 -1 ?0 ?1
> attr(,"tsp")
> [1] ?0 10 ?1
>>
>
> This is very odd. ?What is happening?
>
> I get what I using S[-1] so I have no problem, but I obviously do not
> understand some thing!
>
lag lags the indexes not the data.   Try lag(ts(S))

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