[R] Have a function like the "_n_" in R ? (Automatic count function )

[hadley wickham]

On Wed, Feb 25, 2009 at 8:41 AM, Wacek Kusnierczyk
<Waclaw.Marcin.Kusnierczyk at idi.ntnu.no> wrote:
> hadley wickham wrote:
>> And for completeness here's a function that returns the next integer
>> on each call.
>>
>> n <- (function(){
>>   i <- 0
>>   function() {
>>     i <<- i + 1
>>     i
>>   }
>> })()
>>
>
> actually, you do not need the external function to have the functionality:
>
>    n = local({
>        i = 0
>        function() (i <<- i + 1)[1] })
>
>    n()
>    # 1
>    n()
>    # 2

Yes, I'm just using the function as a way of creating an environment.
The function method is a little more flexible if you want multiple
independent counters though.

Hadley



-- 
http://had.co.nz/