Use a `width` of integer index locations. And you likely want =
"right" (or rollapplyr(), as I used).
R> set.seed(21)
R> x <- rnorm(10)
R> rs <- rollapplyr(x, seq_along(x), sum)
R> cs <- cumsum(x)
R> identical(rs, cs)
[1] TRUE
On Thu, Aug 10, 2017 at 1:28 PM, Christofer Bogaso
<bogaso.christo...@gmail.com> wrote:
> Hi again,
>
> I am wondering there is any function for 'zoo' time series, where I
> can apply a user defined function rolling window basis, wherein window
> size is ever increasing i.e. not fixed. For example, let say I have
> below user defined function and a zoo time series :
>
>> library(zoo)
>
>> UDF = function(x) sum(x)
>
>> TS = zoo(rnorm(10), seq(as.Date('2017-01-01'), as.Date('2017-01-10'), by =
>> '1 day'))
>
>>
>
> Now I want to apply UDF (this can be any custom function, however here
> I put it just quick example) rolling window basis like :
>
> 1st data point = 1st data point of TS
> 2nd data point = sum of 1st and 2nd data points of TS
> 3rd data point = sum of 1st 2nd and 3rd data points of TS
>
> so on
>
> I am aware of the rollapply() function from zoo, however, appears like
> it is only for fixed window size.
>
> Appreciate any pointer how to achieve above strategy of implementing
> rolling calculation based on increased window size.
>
> Thanks for your time.
>
> ______________________________________________
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--
Joshua Ulrich | about.me/joshuaulrich
FOSS Trading | www.fosstrading.com
R/Finance 2017 | www.rinfinance.com
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