[R] functions within a list

baptiste auguie
2009-03-20T09:32:07Z

Hi,


you could have a look at the doBy package which makes these operations
easier. Hadley's plyr package is also another option.

baptiste

On 20 Mar 2009, at 01:01, Altaweel, Mark R. wrote:

> Hi,
>
> I am trying to perform various functions on a list with a number of
> elements. For example. I would like to take the mean of different
> variable values in the entire list. As an example,
> say I have a list with 1000 elements and variables called Id and
> Tick. What I would like to do is take the mean of a variable called
> X for each Tick in the data element. So, there can be say 1 to 600
> tick values per element in a list, that would mean I would like to
> find the 600 mean values for each of the ticks values in the 1000
> elements.
>
>
> I tried a simple attempt below, but I am sure it is way off as it
> didn't produce what I expected:
>
> //res=res[[1..1000]]
> weightX<-sapply(res, function(.df) {mean(.df$X[.df$Id>0 & .df
> $Tick<601])})
>
> Basically, I was trying to get the mean for all tick values less
> than 600 that have an Id variable greater than 0. So, since there
> are 600 ticks I would like to return a result with 600 mean values,
> for each of the 600 ticks, that factors all the 1000 occurrences of
> each tick, starting from 1.
>
> I hope this is clear. Thanks in advance.
>
> Mark
>
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_____________________________

Baptiste Augui?

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