Here is the script (slightly editted) of the demo of R 
given in lecture on October 17.


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Version 1.8.0  (2003-10-08)

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> 7+9
[1] 16
> a <- 8*7
> a
[1] 56
> 
> 7.9
[1] 7.9
> 
> a<100
[1] TRUE
> 
> as.numeric(a<100)
[1] 1
> 
> 1:3
[1] 1 2 3
> 1:8
[1] 1 2 3 4 5 6 7 8
> c(6,4,9)
[1] 6 4 9
> b<-c(6,4,9)
> b
[1] 6 4 9
> b[2]
[1] 4
> 
> b[2]<-99
> b
[1]  6 99  9
> 
> x <-list(a=9, b=0, c=65)
> x
$a
[1] 9

$b
[1] 0

$c
[1] 65

> x$b
[1] 0
> x$b <- 234
> x
$a
[1] 9

$b
[1] 234

$c
[1] 65

> x$b <-TRUE
> x
$a
[1] 9

$b
[1] TRUE

$c
[1] 65

> square <- function (x) X^2
> square
function (x) X^2
> square(8)
Error in square(8) : Object "X" not found
> square <- function (x) x^2
> square(8)
[1] 64
> 
> function <- 9
Error: syntax error
> 
> flip <- function (p) { u <- runif(1); u<p }
> flip(0.8)
[1] TRUE
> flip(0.8)
[1] TRUE
> flip(0.8)
[1] TRUE
> flip(0.8)
[1] TRUE
> flip(0.8)
[1] TRUE
> flip(0.8)
[1] FALSE
> flip(0.8)
[1] TRUE
> u
Error: Object "u" not found
> # comment
> 
> flip <- function (p) { u <- runif(1);  return (u<p) }
> flip(0.5)
[1] FALSE
> 
> a
[1] 56
> if (a<70) print(99) else print(33)
[1] 99
> while (a>50) { print(a); a <- a-1 }
[1] 56
[1] 55
[1] 54
[1] 53
[1] 52
[1] 51
> a==56
[1] FALSE
> a==50
[1] TRUE
> a!=50
[1] FALSE
> a>=0
[1] TRUE
> a>=0 && a<100
[1] TRUE
> 
> a <- 1 +
+    3
> a
[1] 4
> a <- 1