Hello,
You can't use tab$MVAR but you can use tab[[MVAR]] if you do MVAR <-
"population" (no need for c()).
Hope this helps,
Rui Barradas
Citando Amoy Yang via R-help <r-help@r-project.org>:
> population is the field-name in data-file (say, tab).
> MVAR<-population takes data (in the column of population) rather
> than field-name as done in SAS: %let MVAR=population;
> In the following r-program, for instance, I cannot use ...
> tab$MVAR...or simply MVAR itself since MVAR is defined as
> "population" with double quotes if using MVAR<-c("population")
>
> On Wednesday, February 3, 2016 11:54 AM, Duncan Murdoch
> <murdoch.dun...@gmail.com> wrote:
>
> 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
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.htmland provide commented,
> minimal, self-contained, reproducible code.
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
