[R] Create variables with common values for each group

[Dieter Menne]

Stephan Lindner <lindners <at> umich.edu> writes:


> The problem is to create new variables from a data frame which
> contains both individual and group variables, such as mean age for an
> household. My data frame:
> 
> df 
> 
>        hhid h.age
> 1  10010020    23
> 2  10010020    23
...
> where hhid is the same number for each household, h.age the age for
> each household member. 
> 
> I tried tapply, by(), and aggregate. The best I could get was:
> 
> by(df, df$hhid, function(subset) rep(mean(subset$h.age,na.rm=T),nrow(subset)))
> 
> df$hhid: 10010020
> [1] 23 23
> ------------------------------------------------------------ 
> df$hhid: 10010126
> [1] 51 51

try something like 

do.call("rbind",byresult)

As you did not provide a running example, the suggestion is only approximately
correct.

Dieter