## -----------------------------------------------------------------------------
matrix(ncol=3, nrow=2)


## -----------------------------------------------------------------------------
matrix(1:6, ncol=3, nrow=2)


## -----------------------------------------------------------------------------
matrix(1:6, ncol=3, nrow=2, byrow=TRUE)


## -----------------------------------------------------------------------------
m <- matrix(1:6, ncol=2, nrow=3)
t(m)


## -----------------------------------------------------------------------------
a <- c(1,2,3)
b <- 5:7


## -----------------------------------------------------------------------------
m1 <- cbind(a, b)
m1


## -----------------------------------------------------------------------------
m2 <- rbind(a, b)
m2


## -----------------------------------------------------------------------------
m3 <- cbind(b, b, a)
m <- cbind(m1, m3)
m


## -----------------------------------------------------------------------------
nrow(m)
ncol(m)
# dimensions of m (nrow, ncol))
dim(m)
# number of cells, or nrow(m) * ncol(m)
length(m)


## -----------------------------------------------------------------------------
# get the column names
colnames(m)
# set the column names
colnames(m) <- c('ID', 'X', 'Y', 'v1', 'v2')
m


## -----------------------------------------------------------------------------
rownames(m) <- paste0('row_', 1:nrow(m))
m 


## -----------------------------------------------------------------------------
cbind(vchar=c('a','b'), vnumb=1:2)


## -----------------------------------------------------------------------------
list(1:3)


## -----------------------------------------------------------------------------
e <- list(c(2,5), 'abc')
e


## -----------------------------------------------------------------------------
names(e) <- c('first', 'last')
e


## -----------------------------------------------------------------------------
m <- matrix(1:6, ncol=3, nrow=2)
f <- list(e, m, 'abc')
f


## -----------------------------------------------------------------------------
# four vectors
ID <- as.integer(1:4)
name <- c('Ana', 'Rob', 'Liu', 'Veronica')
sex <- as.factor(c('F','M','M','F'))
score <- c(10.2, 9, 13.5, 18)

d <- data.frame(ID, name, sex, score)
d


## -----------------------------------------------------------------------------
class(d)
length(d)


## -----------------------------------------------------------------------------
is.list(d)
names(d)


## -----------------------------------------------------------------------------
nrow(d)
dim(d)
colnames(d)