RStudio__anonymous.R

############################################################
####              Anonymous functions in R              ####
############################################################

capitals <- c("Amsterdam", "Paris", "Warszawa", "Istanbul")
lapply(capitals, function(name) nchar(name))

# function with no name assigned to it, and does not appear in global env.:
{function(x) x^2}(5)
(function(x) x^2)(4) # without curly brackets

# draw a plot (kinda it is in a loop):
plot(function(x) x^2)

# directly assign value from function:
a <- {function (x,y) x^y} (2,3)
# 'a' returns 8!
a

# In a for loop (obviously not very useful):
L <- list()
for (i in 1:5) {
  L[[i]] <- {function(x) x^2}(i)
}

test <- local({
  function(x) x^2
})
test(5)

##

square_add <- function(x) {
  sq <- x ^ 2
  if (x > 4) {
    function(x) {
      log(x)
    }
  }
  sq
}