Automatically create formulas for all possible linear models

Question

Say I have a training set in a data frame train with columns ColA, ColB, ColC, etc. One of these columns designates a bin

Answer 1

vars<-c('a','b','c','d')
library(gregmisc) 
indexes<-unique(apply(combinations(length(vars), length(vars), repeats=T), 1, unique))
gen.form<-function(x) as.formula(paste('~',paste( vars[x],collapse='+')))
formulas<-lapply(indexes, gen.form)
formulas

Generates:

R> formulas

[[1]] ~a

[[2]] ~a + b

[[3]] ~a + c

[[4]] ~a + d

[[5]] ~a + b + c

[[6]] ~a + b + d

[[7]] ~a + c + d

[[8]] ~a + b + c + d

[[9]] ~b

[[10]] ~b + c

[[11]] ~b + d

[[12]] ~b + c + d

[[13]] ~c

[[14]] ~c + d

[[15]] ~d