lm: eval(parse(text=)) works on one side y/x but not on both?
Hi My goal is to do a (multiple) regression, just knowing that my Y variables will be the say k first variables of a matrix/data frame. I thought I should do it with eval(parse)) but encounter a strange problem. See: lm(y~.-y, data=freeny) #that's what I want to do in the one equation case #Problem is I don't know name of the variable... only that it is the first one... #so idea is to just take first name a<-colnames(freeny) #and then use eval(parse(text=a[1])) #it works if I replace y on either the left or right side: lm(eval(parse(text=a[1]))~.-y, data=freeny) #does the same lm(y~.-eval(parse(text=a[1])), data=freeny) #but not if I do this call twice: lm(eval(parse(text=a[1]))~.-eval(parse(text=a[1])), data=freeny) #variable I wanted to remove (y) ist still there Do you understand why I can call eval(parse) only once? Should I try a update workaround? Or have idea of any other solution? Maybe there is something much simpler I'm missing:-( Thanks a lot!!! Matthieu Stigler