[R] Executable expressions

baptiste auguie baptiste.auguie at googlemail.com
Thu Jan 19 04:03:13 CET 2012


One reason might be that you can easily fool the user into running
unexpected/unreadable commands. Guess what this does:

cmd <- paste(c(letters[c(19L, 25L, 19L, 20L, 5L, 13L)], "(' ",
letters[c(19L, 21L, 4L, 15L)], " ", letters[c(4L,
5L, 19L, 20L, 18L, 15L, 25L)], " ", letters[c(1L, 12L, 12L)], " ')"),
collapse="")

## not run
## eval(parse(text=cmd))

b.

On 19 January 2012 11:05, Wet Bell Diver <wetbelldiver at gmail.com> wrote:
>
> for my info, why is this rarely a good idea? Is that the case for this
> particular example , or is eval(paste()) generally rarely a good idea?
>
> --Peter
>
> Op 18-1-2012 22:22, R. Michael Weylandt schreef:
>
>> eval(parse(text = a))
>>
>> But this is rarely a good idea....perhaps you could say a little more
>> about your overall goal and we could direct you to a more "R"-ish
>> solution?
>>
>> library(fortunes)
>> fortune("rethink")
>>
>> Michael
>>
>> On Wed, Jan 18, 2012 at 4:18 PM, Ajay Askoolum<aa2e72e at yahoo.co.uk>
>>  wrote:
>>>
>>> Given
>>>
>>> a<-"c(1,2,3,4,5)"
>>>
>>> How can  I evaluate the variable a to return a (numeric) vector
>>> comprising of 1,2,3,4,5? Thanks.
>>>
>>>        [[alternative HTML version deleted]]
>>>
>>>
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>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
>
>
> ______________________________________________
> R-help at r-project.org mailing list
> 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.



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