99-R-exercises

Reproductible research with R

require(compiler)
enableJIT()

## Error in enableJIT(): argument "level" is missing, with no default

# ex1 : Find the last element of a vector
find("letters")

## [1] "package:base"

str(letters)

##  chr [1:26] "a" "b" "c" "d" "e" "f" "g" "h" "i" ...

letters

##  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q"
## [18] "r" "s" "t" "u" "v" "w" "x" "y" "z"

letters[length(letters)]

## [1] "z"

# ex2 : Find the last but one element of a vector
letters[length(letters) - 1]

## [1] "y"

# ex3 : Find the Kth element in a vector
letters[13]

## [1] "m"

# ex4 : Find number of elements in the vector
length(letters)

## [1] 26

N <- 0
L <- 1:length(letters)

for(i in L) {
    N <- N + 1
}

cat("number= ", N, "\n") 

## number=  26

# http://homepage.stat.uiowa.edu/~luke/R/compiler/compiler.pdf