[plyr] Question regarding ddply: use of .(as.name(varname)) and varname in ddply function
On Mon, Dec 6, 2010 at 3:58 AM, Sunny Srivastava
<research.baba at gmail.com> wrote:
Dear R-Helpers: I am using trying to use *ddply* to extract min and max of a particular column in a data.frame. I am using two different forms of the function: ## var_name_to_split is a string -- something like "var1" which is the name of a column in data.frame ddply( df, .(as.name(var_name_to_split)), function(x) c(min(x[ , 3] , max(x[ , 3]))) ## fails with an error - case 1 ddply( df, var_name_to_split , function(x) c(min(x[ , 3] , max(x[ , 3]))) ? ? ? ? ? ? ? ## works fine - case 2 I can't understand why I get the error in case 1. Can someone help me please?
Why do you expect case 1 to work? Hadley
Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/