Dennis & Hadley, This does exactly what I need — thank you so much!
Regards, Tom On 10/4/11 5:34 PM, Dennis Murphy wrote:
Hi Hadley: When I tried your function on the example data, I got the following: dd<- data.frame(year = rep(2000:2008, each = 500), y = rnorm(4500)) g<- function(df, qs = c(.05, .25, .50, .75, .95)) { data.frame(q = qs, quantile(d$y, qs)) } ddply(dd, .(year), g)ddply(dd, .(year), g)year q quantile.d.y..qs. 1 2000 0.05 NA 2 2000 0.25 NA 3 2000 0.50 NA ... 43 2008 0.50 NA 44 2008 0.75 NA 45 2008 0.95 NA Warning messages: 1: In is.na(x) : is.na() applied to non-(list or vector) of type 'NULL' 2: In is.na(x) : is.na() applied to non-(list or vector) of type 'NULL' <repeated once per year> This, however, does work (with a likely fix to the variable name afterwards): g<- function(df, qs = c(.05, .25, .50, .75, .95)) { data.frame(q = qs, quantile(d[, 2], qs)) }ddply(dd, .(year), g)year q quantile.d...2...qs. 1 2000 0.05 -1.36670724 2 2000 0.25 -0.97786897 3 2000 0.50 -0.05982217 4 2000 0.75 0.33576399 5 2000 0.95 1.30389105 ... Dennis On Tue, Oct 4, 2011 at 12:10 PM, Hadley Wickham<had...@rice.edu> wrote:# Function to compute quantiles and return a data frame g<- function(d) { qq<- as.data.frame(as.list(quantile(d$y, c(.05, .25, .50, .75, .95)))) names(qq)<- paste('Q', c(5, 25, 50, 75, 95), sep = '') qq }You could cut out the melt step by making this return a data frame: g<- function(df, qs = c(.05, .25, .50, .75, .95)) { data.frame(q = qs, quantile(d$y, qs)) } Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/
-- Thomas E Adams National Weather Service Ohio River Forecast Center 1901 South State Route 134 Wilmington, OH 45177 EMAIL: thomas.ad...@noaa.gov VOICE: 937-383-0528 FAX: 937-383-0033 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
