[R] Create variable by name

[Ralf B]

Hi all,

I have scripts that have one variable called 'output', the script
creates a data frame and stores this data frame in 'output'. Then
the data frame is written to disk. This is simple when working with a
single script. However, as soon as one script calls other, variables
overwrite each other.

Here a little example that fixes the problem for one particular case
by using variables with different names:


#
# Script A, either called directly or from another script
#
outputA <- NULL
getOutput <- function(){
      return(outputA)
}
outputA <- "script A"

#
# Script B, includes and executes script A as part of its own
#
output <- NULL
output <- "Script B"
source("C:/data/poodle/coder/overwritingTest/scriptA.R")
outputA <- getOutput()
print(paste("Output script B:", output))
print(paste("Output script A:", outputA ))

However, I simply want to ensure that script A's output does not interfere with
the the one produced by script B without script B's need to know how A called
its variable. I want script B to easily access the output of script A.
What I would
ideally need ( I think) is an OO approach. I was thinking that I could perhaps
store a generic variable that is generated based on the script name
(i.e. scriptA_output, scriptB_output)

On Wed, Oct 6, 2010 at 1:24 PM, Greg Snow <Greg.Snow at imail.org> wrote:
> Possible? Yes (as others have shown), advisable? No, see fortune(106), fortune(236), and possibly fortune(181).
>
> What is your ultimate goal? Maybe we can help you find a better way.
>
> --
> Gregory (Greg) L. Snow Ph.D.
> Statistical Data Center
> Intermountain Healthcare
> greg.snow at imail.org
> 801.408.8111
>
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of Ralf B
>> Sent: Wednesday, October 06, 2010 10:32 AM
>> To: r-help Mailing List
>> Subject: [R] Create variable by name
>>
>> Can one create a variable through a function by name
>>
>> createVariable <- function(name) {
>>       outputVariable = name
>>       name <- NULL
>> }
>>
>> after calling
>>
>> createVariable("myVar")
>>
>> I would like to have a variable myVar initialized with NULL in my
>> environment. Is this possible?
>>
>> Ralf
>>
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.
>