x <- c(1, 3, 2, 5)
x

x = c(1,6,2)
x

y = c(1,4,3)
y

length(x)

length(y)

x+y

ls()

rm(x, y)

ls()

rm(list=ls())

?matrix

x = matrix(data = c(1,2,3,4), nrow = 2, ncol = 2)
x

x = matrix(c(1,2,3,4),2,2)

matrix(c(1,2,3,4), 2, 2, byrow=TRUE)

sqrt(x)

x^2

x = rnorm(50)
y = x + rnorm(50, mean=50, sd=.1)
cor(x, y)

set.seed(1145)
rnorm(10)

set.seed(3)
y = rnorm(100)
mean(y)

var(y)

sqrt(var(y))

sd(y)

x = rnorm(100)
y = rnorm(100)
plot(x, y)

plot(x, y, xlab="Toto je x-ová os", ylab="Toto je y-ová os", main="Graf X vs Y")

pdf("ISLR - 1. Úvod do jazyka R - Graf.pdf")
plot(x, y, col = "green")
dev.off()

x = seq(1, 10)
x

x = 1:10
x

x = seq(-pi, pi, length = 10)
x

y = x
f = outer(x, y, function(x, y)cos(y)/(1 + x^2))     
contour(x, y, f) 

pdf("ISLR - 1. Úvod do jazyka R - Graf Contour.pdf")
contour(x, y, f, nlevels = 45)
dev.off()     
contour(x, y, f, nlevels = 45)

fa = (f - t(f)) / 2 
contour(x, y, fa, nlevels = 15) 

image(x, y, fa)

persp(x, y, fa)

persp(x, y, fa, theta = 30)

persp(x, y, fa, theta = 30, phi = 20)

persp(x, y, fa, theta = 30, phi = 70)

persp(x, y, fa, theta = 30, phi = 40)

A = matrix( 1:16, 4, 4)

A[2, 3]

A[c(1,3), c(2,4)]

A[1:3, 2:4]

A[1:2, ]

A[ , 1:2 ]

A[1, ]

A[ -c( 1, 3), ]

dim(A)

Auto = read.table("Auto.data")

fix(Auto)

Auto = read.table("Auto.data", header = TRUE, na.string = "?")

fix(Auto)

Auto = read.csv("Auto.csv", header = TRUE, na.string= "?" )

fix(Auto)

dim(Auto)

Auto[1:4, ]

Auto = na.omit(Auto)

dim(Auto)

names(Auto)

plot(Auto$cylinders, Auto$mpg)

attach(Auto)

plot(cylinders, mpg)

cylinders = as.factor(cylinders)

plot(cylinders, mpg)

plot(cylinders, mpg, col = "red")

plot(cylinders, mpg, col = "red", varwidth=TRUE)

plot(cylinders, mpg, col = "red", varwidth = TRUE, horizontal = TRUE)

plot(cylinders, mpg, col = "red", varwidth=TRUE, xlab = "cylinders")

hist(mpg)

hist(mpg, col = 2)

hist(mpg, col = 2, breaks = 15)

pairs(Auto)

pairs(~ horsepower + weight + acceleration, Auto)

pairs(~ mpg + displacement + horsepower + weight + acceleration, Auto)

plot(horsepower, mpg)
identify(horsepower,mpg,name)

summary(Auto)

summary(mpg)

q()