Variable name restrictions in R

Question

What are the restrictions as to what characters (and maybe other restrictions) can be used for a variable name in R?

(This screams of general reference, but I can\'t

Answer 1

Using the make.names() function from the built in base package may help:

is_valid_name<- function(x)
{
  length_condition = if(getRversion() < "2.13.0") 256L else 10000L
  is_short_enough = nchar(x) <= length_condition
  is_valid_name = (make.names(x) == x)

  final_condition = is_short_enough && is_valid_name
  return(final_condition)
}