[R] how to find interval?

[Patrick Burns]

I believe you want to use 'diff' and 'which' as in:

 > diff(which(c(TRUE, 1:10 %in% c(3, 5, 6, 10) )))
[1] 3 2 1 4


Pat

On 17/09/2013 11:15, gildororonar at mail-on.us wrote:
> 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:)
>
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