R help - Mar 2004 - Calculating percentiles from Grouped Data (gapply)

Dear R-list,

I try to calculate the 10- and 90-Percentile from grouped data.
Using 'lappy' it works fine but I have no success with 'gapply':
 
df <- data.frame(test = runif(100))
df <- df[order(df[,1]),]
z <- rep(1:10, each = 10)
lapply(split(df, z), function(x) quantile(x, probs=c(10,90)/100))

library(nlme)
gapply(as.data.frame(df), which=1, 
          function(x) quantile(x, probs=c(10,90)/100), group=z)
#  Error in sort(x, partial = unique(c(lo, hi))) : 
#    `x' must be atomic

Thanks for any help
Patrick

Patrick Hausmann wrote:
> 
> Dear R-list,
> 
> I try to calculate the 10- and 90-Percentile from grouped data.
> Using 'lappy' it works fine but I have no success with
'gapply':
> 
> df <- data.frame(test = runif(100))
> df <- df[order(df[,1]),]
> z <- rep(1:10, each = 10)
> lapply(split(df, z), function(x) quantile(x, probs=c(10,90)/100))
> 
> library(nlme)
> gapply(as.data.frame(df), which=1,
>           function(x) quantile(x, probs=c(10,90)/100), group=z)
> #  Error in sort(x, partial = unique(c(lo, hi))) :
> #    `x' must be atomic

For use with quantile(), you have to make x in your anonymous function a
vector as in:

  gapply(as.data.frame(df), which=1,
      function(x) quantile(x[[1]], probs=c(10,90)/100), group=z)


Uwe Ligges
> Thanks for any help
> Patrick
> 
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