Run linear models by group over list of variables in R

Question

I have a data frame and I need to run 6 2-variable linear models for each group \'site\'. Then, I need to convert the results to a data frame. The second variable in the linear

Answer 1

I am not sure if this is exactly what you are trying to do, but the data.table plyr package allows you to run models split by multiple variables. Below is an example, with var1 and var2 simply representing two variables you want each combination of values to be modeled separately.

#load packages
library(data.table)
library(plyr)

#break up by variables, then fit the model to each piece
models <- dlply(data, c("var1","var2"),
              function(data)
                lm(DV ~ 
                     IV1 + IV2
                   , data = data, weights = weights))
#apply coef to eah model and return a df
models_coef <- ldply(models, coef)
#print summary
l_ply(models_coef, summary, .print = T)