[R] How to define a variable in a function that another function uses without using global variables

R. Michael Weylandt michael.weylandt at gmail.com
Wed Jan 18 19:51:43 CET 2012


Consider this example:

power <- function(n){
    function(x) x^n
} # Note that this function returns a function!

cube <- power(3)

cube(2) # gives 8

That make sense?

Michael

On Wed, Jan 18, 2012 at 1:30 PM, statguy <martinju at mail.com> wrote:
> I would like to know if it is possible to make a function that defines a
> variable in another function without setting that variable globally?
>
> I would i.e. be able to define a variables value inside a function ("one
> level above) which another function makes use of, without setting this
> variable globally.
>
> I have provided this very simple illustrating example.
>
> test1=function(x)
>        {
>        x+y
>        }
> test2=function(y1)
>        {
>        y=y1
>        test1(2,y1)
>        }
>
> Running the second function results in an error:
>> test2(1)
> Error in test1(2) : object 'y' not found
>
> I see 2 possible solutions to this, but neither of them is preferred in my
> more complex situation:
>
> 1. Setting y<<-y_1 globally in test2-function
> 2. making test1 a function of both x and y.
>
> Is there any other way to do this except from the 2 above? I hope someone
> can help me with this.
>
> --
> View this message in context: http://r.789695.n4.nabble.com/How-to-define-a-variable-in-a-function-that-another-function-uses-without-using-global-variables-tp4307604p4307604.html
> Sent from the R help mailing list archive at Nabble.com.
>
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