Defining a function in R, looks like
mynewsumfunction <- function(x,y = 34){
x + y
}
Parameters can have a default value.
If parameters are strings you can use function paste
paste(c("The", "quick", "brown", "fox"))
[1] "The" "quick" "brown" "fox"
Ellipsis allows to declare a variable number of parameters in a function.
> myhist <- function(x, border="blue", ...){
+ hist(x, border=border, ...)
+ }
> set.seed(5)
> myhist(rnorm(1000), breaks=30)
> set.seed(5)
> myhist(rnorm(1000))
Function prototypes can be checked with args function:
args(mean) function (x, ...)
Environments:
Every function and symbol has to be defined in an environment:
- global
- packages loaded
- package base
search (myfunction)
Functions can be defined within other functions.
environment(myfunction)
