(1:10) > 5
1 > 5
2 > 5
3 > 5
rep( 5, 10 )
(1:10) > rep( 5, 10 )
c( 1 , "A" )
x <- c( 1, 2, 3, "A" )
x
as.numeric( x )
"1" > "5"
"6" > "5"
"10" > "5"
"1" > "5"
x <- c("cat", " dog", "mouse" )
f <- factor(c)
x <- c("cat", " dog", "mouse" )
f <- factor( x )
f
x == "cat" 
x == "dog"
x == "mouse" 
levels(f)
grade.levels <- factor( c(12, 16, 12, 7, 7, 5, 6, 5, 9, 10) )
grade.levels 
class( grade.levels )
mode( grade.levels )
mean( grade.levels )
mean( as.numeric( grade.levels ) )
as.numeric( grade.levels )
as.character( grade.levels )
as.numeric( as.character( grade.levels ) )
"adam" > "abram"
"A" > "a"
"a" > "A"
"Aaron" > "abram"
calcMortgage <- function( principal, years=30, APR=0.05 )
 {
    months <- years * 12   # covert years to months
    int.rate <- APR / 12   # convert annual rate to monthly
    # amortization formula
    monthly.payment <- ( principal * int.rate ) / 
                       (1 - (1 + int.rate)^(-months) )
    monthly.payment <- round( monthly.payment, 2 )
    return( monthly.payment )
 }
calcMortgage( principal=100000, years=15, APR=0.03 )
calcMortgage( principal=100000, years=15, APR=0.03 )
args( calcMortgage )
calcMortgage( principal=100000 )
calcMortgage( principal=100000 )
calcMortgage(  )
calcMortgage( years=30 )
calcMortgage( principal=100000, years=15, APR=0.07 )
calcMortgage( years=30 )
calcMortgage( principal=100000, years=30, APR=0.05 )
args( calcMortgage )
calcMortgage( 100000, 30, 0.05 )
calcMortgage( 100000 )
calcMortgage( years=30, principal=100000, APR=0.05 )
calcMortgage( principal=100000, years=30, APR=0.05 )
calcMortgage( 30, 100000, 0.05 )
calcMortgage( principal=100000, years=30, APR=0.05 )
calcMortgage( 100000, 30, 0.05 )
calcMortgage(  30, 0.05, principal=100000 )
args( calcMortgage )
calcMortgage(  0.05, 30, principal=100000 )
calcMortgage( principle=100000 )
calcMortgage(  )
calcMortgage( prin=100000 )
calcMortgage( prin=100000, years=30, APR=0.05 )
calcMortgage( prin=100000, y=30, A=0.05 )
calcMortgage( p=100000, y=30, A=0.05 )
calcMortgage( p=100000,  A=0.05, y=30 )
calcMortgage( P=100000, a=0.05, y=30 )
calcMortgage( Principal=100000, APR=0.05, y=30 )
calcMortgage( prin=c(100000,200000), APR=0.05, y=30 )
calcMortgage( principal="100000", APR=0.05, y=30 )
x <- 1:100
y <- 2*x + rnorm(100,0,10)
plot( x, y, xlim=c(0,100) )
plot( x, y, xlim=c(0,100), pch=19, col="blue" )
args( plot )
plot( x=x, y=y, xlim=c(100,0), pch=19, col="blue" )
plot( x=x, y=y, xlim=100, pch=19, col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch="16", col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch="19", col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch=16, col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch=11, col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch="9", col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch="$", col="blue" )
plot( x=x, y=y, xlim=c(0,100), pch="64", col="blue" )
16
blue
x <- c(1000000,2000000)
x
class( x )
m <- lm( y ~ x )
m
x <- 1:100
y <- 2*x + rnorm(100,0,10)
m <- lm( y ~ x )
m
class( m )
m
class( m )
summary( m )
names( m )
plot( m )
plot( x, y )
cut(x,10)
table( cut( x, 10 ) )
x <- rnorm(100) 
y <- 2*x + rnorm(100,0,10)
plot( x )
plot( x, y  )
table( cut( x, 10 ) )
hist( x ) 
cut(x,10)
plot( x , y )
plot( y, cut(x,10) )
plot( cut(x,10), y )
plot( x, pch=19, col="blue" )
length(x)
plot( sort(x), pch=19, col="blue" )
d <- data.frame(x,y)
plot( d )
plot( d , pch=19, col="blue" )
ls()
class( x )
class( m )
summary( x )
class( x )
summary( m )
ls()
class( "calcMortgage" )
class( calcMortgage )
calcMortgage
plot
args( plot )
c("cat","dog","mouse") == "dog"
d <- 
structure(list(name = structure(c(1L, 4L, 3L, 2L), .Label = c("frank", 
"nancy", "sanjay", "wanda"), class = "factor"), gender = structure(c(2L, 
1L, 2L, 1L), .Label = c("female", "male"), class = "factor"), 
    group = structure(c(2L, 2L, 1L, 1L), .Label = c("control", 
    "treat"), class = "factor"), strength = c(27, 43, 19, 58)), .Names = c("name", 
"gender", "group", "strength"), row.names = c(NA, -4L), class = "data.frame")
d
d$group == "treat" & d$gender == "male" 
these <- d$group == "treat"
these 
these <- d$group == "treat" & d$gender == "male" 
class( these )
sum( these ) 
these
these <- d$group == "treat" & d$gender == "male" 
dat[ these , ]
d[ these , ]
these <- d$group == "treat"
d[ these , ]
sum( these )   
mean( these )
mean( d$strength[ d$group == "treat" ]   )
mean( d$strength[ d$group == "control" ] )
d.treated <- d[ d$group == "treat" , ]
gender <- sample( c("male","female"), size=10, replace=TRUE )
beard  <- sample( c("yes","no"), size=10, replace=TRUE )
gender
beard
gender[  gender == "male"  ]
 gender == "male" 
gender != "male"
gender[  gender != "male"  ]
gender == "male" 
! gender == "male"
gender[  ! gender == "male"  ]
gender[  gender != "male"  ]
gender[  ! gender == "male"  ]
x <- c("cat","dog","mouse")
x[ x == "cat" ]
x[ x != "cat" ]
x[ ! x == "cat" ]
x == "cat" 
gender
gender = "male"
gender
gender[  gender = "male"  ]
gender <- sample( c("male","female"), size=10, replace=TRUE )
x = rnorm(100) 
y = 2*x + rnorm(100,0,10)
plot( x=x, y=y, xlim=c(0,100), pch=16, col="blue" )
x = rnorm(100) 
y = 2*x + rnorm(100,0,10)
plot( x=x, y=y, pch=16, col="blue" )
m <- lm(   y   ~  x      )   
x <- 1:100
x
1:100 -> x
x
d <- data.frame( gender, beard )
d
d[    gender == "male" & beard == "yes"  ,  ]
d[    gender == "male" | beard == "yes"  ,  ]
d[    gender != "male" & beard != "yes"  ,  ]
d
d[  ! gender == "male" & beard == "yes"  ,  ]
d[    gender != "male" & beard != "yes"  ,  ]
d[  ! gender == "male" & beard == "yes"  ,  ]
6 + 4 / 2
( 6 + 4 ) / 2
d[  ! ( gender == "male" & beard == "yes" )  ,  ]
d[    gender != "male" & beard != "yes"  ,  ]
d[    gender != "male" & beard != "yes"  ,  ]
class(d)
gender
beard
d[  ! ( gender == "male" & beard == "yes" )  ,  ]
gender == "male" & beard == "yes"
d[    gender == "male" & beard == "yes"  ,  ]
 gender == "male"
sample( x=c("goat","goat","car"), size=3, replace=F )
sample( x=c("goat","goat","car"), size=3, replace=F )
a.game <- sample( x=c("goat","goat","car"), size=3, replace=F )
create_game <- function( )
{
    a.game <- sample( x=c("goat","goat","car"), size=3, replace=F )
    return( a.game )
}
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
create_game()
sample( x=c("goat","goat","car"), size=3, replace=F )
create_game()
create_game()  
create_game() 
create_game() 
args(   sampple )
args(   sample )
  doors <- c(1,2,3) 
sample( doors, size=1 )
sample( doors, size=1 )
sample( doors, size=1 )
select_door <- function( )
{
  doors <- c(1,2,3) 
  a.pick <- sample( doors, size=1 )
  return( a.pick )  # number between 1 and 3
}
select_door()
select_door()
select_door()
select_door()
select_door()
select_door()
select_door()
select_door()
select_door()
this.game <- create_game()
this.game
my.initial.pick <- select_door()
my.initial.pick
this.game
this.game
my.initial.pick
game <- c("car","goat","goat")
 a.pick <- 3
doors <- c(1,2,3)
a.pick
doors != a.pick
doors == "goat"
game
game == "goat"
game == "goat"
doors != a.pick
game == "goat" & doors != a.pick
game
doors[ game == "goat" & doors != a.pick ]
open_goat_door <- function( game, a.pick )
{
   # YOUR CODE HERE...
   # game <- c("car","goat","goat")
   # a.pick <- 3
   doors <- c(1,2,3)
   opened.door <- doors[ game == "goat" & doors != a.pick ]
   return( opened.door ) # number between 1 and 3
}
open_goat_door( game=this.game, a.pick=my.initial.pick )
this.game
my.initial.pick <- 1
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door <- function( game, a.pick )
{
   # YOUR CODE HERE...
   # game <- c("car","goat","goat")
   # a.pick <- 3
   doors <- c(1,2,3)
   possible.doors <- doors[ game == "goat" & doors != a.pick ]
   opened.door <- sample( possible.doors, size=1 )
   return( opened.door ) # number between 1 and 3
}
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
open_goat_door( game=this.game, a.pick=my.initial.pick )
a.pick
! a.pick
args( change_door )
ls()