[R] how to find interval?

[gildororonar at mail-on.us]

I can do this:

> 1:10 %in% c(3, 5, 6, 10)
  [1] FALSE FALSE  TRUE FALSE  TRUE  TRUE FALSE FALSE FALSE  TRUE

but what I wish to get is:

[1] 3 2 1 4

let me explain:

3 # [1:3] ends with TRUE, i.e. FALSE FALSE  TRUE
2 # [4:5] ends with TRUE, i.e. FALSE  TRUE
1 # [6:6] ends with TRUE, i.e. TRUE
4 # [7:10] ends with TRUE, i.e. FALSE FALSE FALSE TRUE

That is, %in% gave me a serial whether or not the element is in a set,  
the length is equal to the former, i.e. 1:10

But I wish to get a serial of intevals of occurance of the element in  
the set, the length is equal to the latter i.e. c(3, 5, 6, 10)

With ths task of finding the intervals, I found, with googling, a  
function called findInterval. I did read every line of that manual,  
and it seems to be for a completely different purpose.

Kindly help the poor newbie:)