X = 34
Y = 3

X + Y
X - Y
X * Y
X ^ Y
X %% Y
class(X)

A = 'Helsinki'
B = 'Warsaw'
C = 'Stockholm'
D = 'Budapest'

class(A)

v <- c(3, 6, 9, 15)
w <- c(4, 6, 8, 12)

v + w

cities <- c(A, B, C, D)

cities

names(w) <- c(A, B, C, D)

w

w[3]

w['Stockholm']

w[c(2, 3)]

w[c(2:4)]

mean(w)

w > 7

w[w>7]

matrix(1:12, byrow=TRUE, nrow=3)

matrix(1:12, byrow=FALSE, nrow=3)

v <- c(3, 6, 9, 15)
w <- c(4, 6, 8, 12)
v_w <- c(v, w)

v_w

v_w_mat <- matrix(v_w, byrow=TRUE, nrow=4)

v_w_mat

mat_A <- matrix(1:9, byrow=TRUE, nrow=3)
print(mat_A)

rownames(mat_A) <- c('Row 1', 'Row 2', 'Row 3')
colnames(mat_A) <- c('Col 1', 'Col 2', 'Col 3')

print(mat_A)

rowSums(mat_A)

colSums(mat_A)

mat_B = matrix(2:10, byrow = FALSE, nrow = 3)
mat_B

mat_A + mat_B

mat_A * mat_B

mat_A / mat_B

mat_A %*% mat_B # matrix multiplication

cbind(mat_A, mat_B)

rbind(mat_A, mat_B)

ls()

mat_C = matrix(1:30, byrow=TRUE, nrow=5)

mat_C

mat_C[,5]

mat_C[3,]

mat_C[2:5,4]