1、按照下列要求操作:
(1)定义一个POSIXlt 类型的时间变量 R语言作业提交截止时间: DDL:“2019-08-01 23:59:59”
(2)显示POSIXlt 列表中hour对应的数值
DDL <- as.POSIXlt("2019-08-01 23:59:59")
DDL$hour#
2.计算 7+5 ,7-5, 7*5,7/5以及 7^5
7+5
7-5
7*5
7/5
7^5
3.分别输出 7大于5,7小于5,7大于等于5,7小于等于5的值
7>5
7<5
7>=5
7<=5
5>7 & 6*7==42
(5>7) | (6*7==42)
time.factor <-12
time.factor
time.in.years <-2.5
time.factor * time.in.years
#6(1)
a<-c(5,6,3)
b<-c(2,6,4)
#6(2)
a+b
a-b
a*b
a/b
a^b
___
[1] 7 12 7
[1] 3 0 -1
[1] 10 36 12
[1] 2.50 1.00 0.75
[1] 25 46656 81
students<-c("Sean","Louisa","Frank","Farhad","Li") #字符向量
midterm<-c(80,90,93,82,95) #数字向量
students
___
[1] "Sean" "Louisa" "Frank" "Farhad" "Li"
a<-c(4,5,8)
b<-c(1,3,6)
a>b
a<b
a>=b
a<=b
___
[1] TRUE TRUE TRUE
[1] FALSE FALSE FALSE
[1] TRUE TRUE TRUE
[1] FALSE FALSE FALSE
y<-matrix(1:20,nrow = 5,ncol = 4) # 生成一个5行,4列的矩阵
y #所赋数值从左到右一列一列排列
____
[,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