19 Writing Function in R

Simple function R ... with no return value.

say.hello <- function(name){
     print(sprintf("Hello %s!", name))
}
say.hello("World")

Call function with argument name

print.person <- function(name, age, city){
    print(sprintf("%s %d %s", name, age, city))
}
print.person(age = 30, name = "Sam", city = "NY")

Order of the variable does not matter if you pass the argument value by name like the example above

Default value of argument

show.time <- function(tz = ""){
    now = Sys.time()
    if(tz == ""){
        print(now)
    }else{
        print(format(now, tz = tz))
    }
}
show.time("GMT") 
show.time()

Return value

gettime <- function(){
    return Sys.time()
}