[R] Create macro_var in R

[Duncan Murdoch]

On 03/02/2016 12:41 PM, Amoy Yang via R-help wrote:
>   There is a %LET statement in SAS: %let MVAR=population; Thus, MVAR can be used through entire program.
> In R, I tried MAVR<-c("population"). The problem is that MAVR comes with double quote "...." that I don't need. But MVAR<-c(population) did NOT work out. Any way that double quote can be removed as done in SAS when creating macro_var?
> Thanks in advance for helps!

R doesn't have a macro language, and you usually don't need one.

If you are only reading the value of population, then

MAVR <- population

is fine.  This is sometimes the same as c(population), but in general 
it's different:  c() will remove some attributes, such as
the dimensions on arrays.

If you need to modify it in your program, it's likely more complicated.  
The normal way to go would be to put your code in a function, and have 
it return the modified version.  For example,

population <- doModifications(population)

where doModifications is a function with a definition like

doModifications <- function(MAVR) {
    # do all your calculations on MAVR
    # then return it at the end using
    MAVR
}

Duncan Murdoch