I guess I wrote my R “hello world!” function 7 or 8 years ago while approaching R for the first time. And it is too little to illustrate the basic syntax of a programming language for a working program to a wannabe R programmer. Thus, here follows a collection of basic functions that may help a bit more than the famed piece of code.

######################################################
############### Hello world functions ################
######################################################
##################################
# General info
fun <- function( arguments ) { body }


##################################
foo.add <- function(x,y){
  x+y
}

foo.add(7, 5)

----------------------------------

foo.above <- function(x){
  x[x>10]
}

foo.above(1:100)

----------------------------------

foo.above_n <- function(x,n){
  x[x>n]
}

foo.above_n(1:20, 12)

----------------------------------

foo = seq(1, 100, by=2)
foo.squared = NULL

for (i in 1:50 ) {
  foo.squared[i] = foo[i]^2
}

foo.squared

----------------------------------

a <- c(1,6,7,8,8,9,2)

s <- 0
for (i in 1:length(a)){
  s <- s + a[[i]]
}
s

----------------------------------

a <- c(1,6,7,8,8,9,2,100)

s <- 0
i <- 1
while (i 

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