R Functions

my_function <- function() { # define function
    print("Hello")
}
my_function() # call function

greet <- function(name) { # parameter
    paste("Hello", name)
}
greet("John") # call with argument

add <- function(a, b) {
    result <- a + b
    return(result) # explicit return
}
multiply <- function(a, b) {
    a * b # implicit return (last value)
}

power <- function(x, n = 2) { # default value
    x ^ n
}
power(5) # uses default n=2
power(5, 3) # n=3

stats <- function(x) { # return multiple values
    list(
        mean = mean(x),
        median = median(x),
        sd = sd(x)
    )
}

sapply(x, function(x) x^2) # inline anonymous function