创建四个成份的列表：字符串、数值型向量、矩阵以及字符型向量。组合可以任意，最后保存为列表。

> g <- "My First List"

> h <- c(25,26,18,39)

> j <- matrix(1:10, nrow = 5)

> k <- c("one","two","three")

> mylist <- list(title=g,ages=h,j,k)

> mylist
$title
[1] "My First List"

$ages
[1] 25 26 18 39

[[3]]
     [,1] [,2]
[1,]    1    6
[2,]    2    7
[3,]    3    8
[4,]    4    9
[5,]    5   10

[[4]]
[1] "one"   "two"   "three"


> mylist[[2]]
[1] 25 26 18 39