矩阵

# 矩阵 ----------------------------------------------------------------------

##创建矩阵
y <- matrix(1:20, nrow = 4, ncol=4)
det(y)
y

cells <- c(1,26,24,66)
cells
rnames <- c('R1','R2')
rnames
cnames <- c('C1','C2')
cnames
mymatrix  = matrix(cells,nrow = 2,ncol = 2,byrow = TRUE, dimnames=list(rnames,cnames))
mymatrix

##矩阵下标
x <- matrix(1:10,nrow = 2)
x
x[2,]
x[,2]
x[1,4]
x[1,c(4,5)]