原理を説明するためにいくつかの方法の虫眼鏡効果の模倣で[css3]css3

> a = c(1, 2, 5, 3, 6, -2, 4) 
> b = c("one", "two", "three") 
> c = c(TRUE, TRUE, TRUE, FALSE, TRUE, FALSE)

> x = matrix(1:20, nrow=5, ncol=4, byrow=TRUE) #generate 1~20, 5 rows, 4 columns, by row
> x
     [,1] [,2] [,3] [,4]
[1,] 1 2 3 4
[2,] 5 6 7 8
[3,] 9 10 11 12
[4,] 13 14 15 16
[5,] 17 18 19 20
> y = matrix(1:20, nrow=5, ncol=4, byrow=FALSE)# generate 1~20, 5 rows, 4 columns, by column
> y
     [,1] [,2] [,3] [,4]
[1,] 1 6 11 16
[2,] 2 7 12 17
[3,] 3 8 13 18
[4,] 4 9 14 19
[5,] 5 10 15 20
> x[2,]# return row 2
[1] 5 6 7 8
> x[,2]#returns column 2
[1] 2 6 10 14 18
> x[1,4]#returns a specified number, row 1, column 4
[1] 4
> x[2,c(2,4)]#returns the specified number, row 2, columns 2 and 4
[1] 6 8
> x[3:5, 2]#returns the specified number, the number of columns 2 of rows 3 through 5
[1] 10 14 18
# name the matrix rows and columns, pay attention to the number of rows and columns to correspond otherwise it will report an error
> rnames=c("apple","banana","orange","melon","corn")
> cnames=c("cat","dog","bird","pig")
> x = matrix(1:20, nrow=5, ncol=4, byrow=TRUE)
> rownames(x)=rnames
> colnames(x)=cnames
> x
       cat dog bird pig
apple 1 2 3 4
banana 5 6 7 8
orange 9 10 11 12
melon 13 14 15 16
corn 17 18 19 20