R help - Apr 2008 - densities from a list with data.frames

Hi there,

I have a list which consists of data frames (all data frames have the same 
amount and type of columns but different length).
Now, I'd like to calculate for each data frame in the list the density
function
of the values of the fist column ($V1).

This list could be an example:

l <- list( data.frame(rnorm(100)), data.frame(rnorm(20)),
data.frame(rnorm(200)) )

Can anybody help? I'm sure there is a nice short way to do this :-)

Antje

> I have a list which consists of data frames (all data frames have the 
same 
> amount and type of columns but different length).
> Now, I'd like to calculate for each data frame in the list the 
> density function 
> of the values of the fist column ($V1).
> 
> This list could be an example:
> 
> l <- list( data.frame(rnorm(100)), data.frame(rnorm(20)), data.
> frame(rnorm(200)) )
If you want to do the same thing to every element of a list, lapply (or 
sapply) is your friend.
Try:

lapply(l, function(x) density(x[,1]))

Regards,
Richie.

Mathematical Sciences Unit
HSL


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