[R] Undefined columns selected

[Jennifer Wessel]

This is part of my program.  I am getting an error, that I cannot figure  out, any help would very much appreciated, thanks.

 	# subset variables 
 	arc <- arc[,c("SNAP", "code",  "ncode", "var", "n_total")]
Error in `[.data.frame`(arc, , c("SNAP", "code", "ncode",  : 
  undefined columns selected
 	arc$N_eff <- with(arc, ifelse(var > 1, n_total, var * n_total))
Error in storage.mode(test) <- "logical" : object 'var' not found