関数を書く

中級 R

Filip Schouwenaars

DataCamp Instructor

自分で書くのはいつ？

my_fun <- function(arg1, arg2) {
  body
}

triple <- function(arg1, arg2) {
  body
}

triple <- function(x) {
  body
}

triple <- function(x) {
  3 * x
}

triple <- function(x) {
  3 * x
}

ls()

"triple"

triple(6)

triple <- function(x) {
  y <- 3 * x
  return(y)
}

triple(6)

my_fun <- function(arg1, arg2) {
  body
}

math_magic <- function(arg1, arg2) {
  body
}

math_magic <- function(a, b) {
  body
}

math_magic <- function(a, b) {
  a*b + a/b
}

math_magic(4, 2)

math_magic(4)

Error: argument "b" is missing, with no default

math_magic <- function(a, b = 1) {
  a*b + a/b
}

math_magic(4)

math_magic(4, 0)

Inf

math_magic <- function(a, b = 1) {
  if(b == 0){
    return(0)
  }
  a*b + a/b
}

math_magic(4, 0)

中級 R