[R] Calculate interaction for a big dataframe

[Arnaud Michel]

Hi

To calculate the value of the interaction between factors of a dataframe 
df, does exist any function which could replace the function when the 
dataframe df has the numbers of rows of df is large (~55000) and also 
the numbers of combinaison of the three factors is large. The calcul abort.
The function to calculate the interaction is :
as.numeric(interaction(df [,c(1:3)],drop=TRUE))

To complete the question and to calculate interaction beetween 3 factors 
f1, f2, f3, does it possible to calculate first f12 = interaction 
(f1,f2) and after calculate interaction (f12, f3).
It seems to me that yes.

Thanks for your help




-- 
Michel ARNAUD
Chargé de mission auprès du DRH
DGDRD-Drh - TA 174/04
Av Agropolis 34398 Montpellier cedex 5
tel : 04.67.61.75.38
fax : 04.67.61.57.87
port: 06.47.43.55.31