[R] functions without arguments

[Petr Klasterecky]

Sure it is possible, but it is a very bad and possibly dangerous idea, 
since you may not control what's passed to your function. Consider this 
example:

 > x <- 1:5
 > x
[1] 1 2 3 4 5
 > foo <- function(){mean(x)}
 > foo()
[1] 3
 > rm('x')
 > foo()
Error in mean(x) : object "x" not found

It is much much beter to include argument(s) and to set them to some 
default value(s):
 > foo <- function(x=c(2,3,1,1,4,5,1)){mean(x)}
 > foo()
[1] 2.428571
 > foo(1:10)
[1] 5.5
 >

Petr

elyakhlifi mustapha napsal(a):
> hello,
> I wanna know if it's possible to write functions without argument 
> in order to understand that I write down an example
> 
> f <- function(){
>  for (i in 1:length(C[[1]]) {
>   print(10*C[[1]][i])
>  }
> }
> 
> I know that there are errors in this syntax
> 
> 
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-- 
Petr Klasterecky
Dept. of Probability and Statistics
Charles University in Prague
Czech Republic