[R] How to assign value to a variable dynamically constructed

Greg Snow 538280 at gmail.com
Wed Jul 8 19:06:19 CEST 2015


This is FAQ 7.21.

The most important part of the answer in FAQ 7.21 is the last section
where it states that it is often easier to use a list rather than
messing around with trying to dynamically name global variables.

If you tell us what you are trying to accomplish then we may have
better advice.  The route you are headed down now usually leads to
inefficient code and hard to find bugs.

On Tue, Jul 7, 2015 at 2:53 PM, Jun Shen <jun.shen.ut at gmail.com> wrote:
> Dear list,
>
> Let's say we have a variable (id), whose name is dynamically constructed.
> This variable represents a vector or data frame with many elements. Now I
> want to specifically assign a value to one of the elements. I couldn't get
> it right.
>
> test <- 'id' # "id" is dynamically constructed through paste()
>
> id <- 1:4
>
> # I can get the element by doing
>
> get(test)[2]
>
> # Now I want to assign a value to the second element of this dynamical
> variable.
>
> get(test)[2] <- 5  # doesn't work.
>
> Thanks a lot.
>
> Jun Shen
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.



-- 
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com



More information about the R-help mailing list