Re: [R] Apply Function to List by Group Returning Result with Dim of List

Excellent. Thank you very much David. Your help is greatly appreciated. "ave" worked like a charm. James -- View this message in context: http://r.789695.n4.nabble.com/Apply-Function-to-List-by-Group-Returning-Result-with-Dim-of-List-tp4311880p4312262.html Sent from the R help mailing list arc

[R] Apply Function to List by Group Returning Result with Dim of List

I have a panel data set defined as a simple data.frame with a factor age and income. I would like to generate the results of a set function such as (sum, mean, or even diff) separate for each factor (category or age group). However I want the result to have the same dimension as the overal data.fra