[R] How to pass different arguments to a function within lapply()?

[David Winsemius]

On Aug 8, 2011, at 11:01 PM, Richard Ma wrote:

> Hi all,
>
> I have a data frame called "rst", see below:
> ------------------------------------------------------------------------------------------
> # This is a paste able example
>
> # In case you don't have "KernSmooth" package installed, please  
> uncomment
> below line.
> # install.packages("KernSmooth")
>
> library(KernSmooth)
>
> rst <- data.frame(hsp = rnorm(23), dal = rnorm(23)
>
> gs <- 350
> ts <- seq(1, 353, 16)
>
> bw <- lapply(rst, dpill, x = ts, gridsize = gs)
>
> # If I just want to apply locpoly function seperately
> lp.hsp <- locpoly(x = ts, y = rst$hsp, bandwidth = bw$hsp, gridsize  
> = gs)
> lp.dal <- locpoly(x = ts, y = rst$dal, bandwidth = bw$dal, gridsize  
> = gs)
> --------------------------------------------------------------------------

 > sapply(c("hsp", "dal"), function(x) locpoly(x=ts, y=rst[[x]],  
bandwidth=bw[[x]], gridsize=gs) )
   hsp         dal
x Numeric,350 Numeric,350
y Numeric,350 Numeric,350


-- 
David.
>
> In above example, I can apply the "locpoly()" to each column of  
> “rst”. But
> if I want to apply this function to all columns of "rst", I guess I  
> should
> use lapply() function.
>
> However, the "bandwidth", one of the locpoly()'s arguments should be
> different due to different columns of "rst". It means that when R  
> apply
> locpoly() to first column "hsp", the "bandwidth" should be set as
> correspondent bandwidth.
>
> My problem is, how to pass the "bandwidth" argument to "locpoly"  
> within
> lapply() in terms of different column names?
>
> My example just tedious if the "rst" has lots of columns. So I  
> wonder if
> there exist more convenient way to get this job done.
>
> Thank you.
>
> -----
> Richard Ma
> PhD student, Ecology & Remote Sensing
> Climate Change Cluster, Department of Environment Science
> University of Technology, Sydney
> --
> View this message in context: http://r.789695.n4.nabble.com/How-to-pass-different-arguments-to-a-function-within-lapply-tp3728858p3728858.html
> Sent from the R help mailing list archive at Nabble.com.
>
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David Winsemius, MD
West Hartford, CT