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Re: Max consecutive increase in sequence

by Tony Plate :: Rate this Message:

If the increases or decreases could be any size,
rle(sign(diff(x))) could do it:

> x <- c(1, 2, 3, 4, 4, 4, 5, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1)
> r <- rle(sign(diff(x)))
> r
Run Length Encoding
lengths: int [1:5] 3 2 2 5 4
values : num [1:5] 1 0 1 -1 0
> i1 <- which(r$lengths==max(r$lengths[r$values==1]) &
r$values==1)[1]
> i2 <- which(r$lengths==max(r$lengths[r$values==-1]) &
r$values==-1)[1]
> i1
[1] 1
> i2
[1] 4
> rbind(up=c(start=cumsum(c(1, r$lengths))[i1],
len=r$lengths[i1]), down=c(start=cumsum(c(1,
r$lengths))[i2], len=r$lengths[i2]))
start len
up 1 3
down 8 5
>

Ingmar Visser wrote:

> rle(diff(sq)) could be helpful here,
> best, Ingmar
>
> On May 13, 2008, at 11:19 PM, Marko Milicic wrote:
>
>> Hi all R helpers,
>>
>> I'm trying to comeup with nice and elegant way of "detecting" consecutive
>> increases/decreases in the sequence of numbers. I'm trying with
>> combination
>> of which() and diff() functions but unsuccesifuly.
>>
>> For example:
>>
>> sq <- c(1, 2, 3, 4, 4, 4, 5, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1);
>>
>> I'd like to find way to calculate
>>
>> a) maximum consecutive increase = 3 (from 1 to 4)
>> b) maximum consecutive decrease = 5 (from 6 to 1)
>>
>> All ideas are highly welcomed!
>>
>>
>>
>>
>>
>> --
>> This e-mail and any files transmitted with it are confid...{{dropped:14}}
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help@... mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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