[R] Function similar to cumsum/cumprod

[Henrique Dallazuanna]

Try this;

set.seed(123)
x <- rnorm(100)
sapply(30:length(x), function(i)mean(x[1:i]))

On Tue, Sep 22, 2009 at 11:12 AM, Sergey Goriatchev <sergeyg at gmail.com> wrote:
> Hello, everyone
>
> I wonder if there is in R somewhere a function similar to cumsum().
> The function calculates a statistic (say mean or standard deviation)
> buy adding consequtively one more data point.
>
> So, say I have a timeseries of 100 observations.
> I start by calculating mean of first 30 observations
> Then I add one observation and calculate mean of 31 observations
> Then I add one more observation and calculate mean of 32 observation,
> and so on until the end
>
> Is there a function like that in R?
>
> Best,
> Sergey
>
> --
> Kniven skärpes bara mot stenen.
>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O