[R] Which "apply" function to use?

[cls59]

Masca, N. wrote:
> 
> Dear All,
> 
> I have a problem which *should* be pretty straightforward to resolve - but
> I can't work out how!
> 
> I have a list of 3 coefficient estimates for 4 different datasets:
> 
> Coefs<-list(c(1,0.6,0.5),c(0.98,0.65,0.4),c(1.05,0.55,0.45),c(0.99,0.50,0.47))
> 
> All I want to do is take the sum (or mean) of each coefficient across the
> 4 datasets.  
> 
> I can do this using a "for" loop, but it gets very messy - as I need to do
> this several times I was hoping someone might have a better solution using
> one of the "apply" functions.  Any ideas?
> 
> Many thanks for any help you can provide.
> 
> Cheers,
> 
> Nick
> 
> 


Since Coefs is a list object you could use the lapply "list apply" function
to execute the mean() function on each component of the list:

lapply( Coefs, mean )

You could also use it to execute your own function that contains additional
operations:

lapply( Coefs, function( listComponent ){

  # Do whatever.

  mean( listComponent )

})

However, I don't know what you mean by these "coefficients" you want to
apply to each of the four data sets. Perhaps you could elaborate?

-Charlie

-----
Charlie Sharpsteen
Undergraduate
Environmental Resources Engineering
Humboldt State University
-- 
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