R语言基本语法（中）

运算符
加减乘除和py一样

%% 两个向量求余

v <- c( 2,5.5,6)
t <- c(8, 3, 4)
print(v%%t)

它产生以下结果 -

[1] 2.0 2.5 2.0

v％/％两个向量相除求商

v <- c( 2,5.5,6)
t <- c(8, 3, 4)
print(v%/%t)
它产生以下结果 -

[1] 0 1 1

^ 将第二向量作为第一向量的指数

v <- c( 2,5.5,6)
t <- c(8, 3, 4)
print(v^t)
它产生以下结果 -

[1]  256.000  166.375 1296.000

|| 称为逻辑OR运算符。取两个向量的第一个元素，如果其中一个为TRUE，则给出TRUE

v <- c(0,0,TRUE,2+2i)
t <- c(0,3,TRUE,2+3i)
print(v||t)
它产生以下结果 -

FALSE

<−
or
=
<<−

称为左分配

v1 <- c(3,1,TRUE,2+3i)
v2 <<- c(3,1,TRUE,2+3i)
v3 = c(3,1,TRUE,2+3i)
print(v1)
print(v2)
print(v3)
它产生以下结果 -

3+0i 1+0i 1+0i 2+3i
3+0i 1+0i 1+0i 2+3i
3+0i 1+0i 1+0i 2+3i

->
bnor
->>

称为右分配

c(3,1,TRUE,2+3i) -> v1
c(3,1,TRUE,2+3i) ->> v2 
print(v1)
print(v2)
它产生以下结果 -

3+0i 1+0i 1+0i 2+3i
3+0i 1+0i 1+0i 2+3i

冒号运算符。它为向量按顺序创建一系列数字。

v <- 2:8
print(v) 
它产生以下结果 -

2 3 4 5 6 7 8

%in% 此运算符用于标识元素是否属于向量

v1 <- 8
v2 <- 12
t <- 1:10
print(v1 %in% t) 
print(v2 %in% t) 
它产生以下结果 -

TRUE
FALSE

%*% 此运算符用于将矩阵与其转置相乘。

M = matrix( c(2,6,5,1,10,4), nrow = 2,ncol = 3,byrow = TRUE)
t = M %*% t(M)
print(t)
它产生以下结果 -

      [,1] [,2]
[1,]   65   82
[2,]   82  117

在这里插入图片描述
获取已安装的所有软件包列表
library()

if 语句

x <- c("what","is","truth")

if("Truth" %in% x) {
   print("Truth is found")
} else {
   print("Truth is not found")
}

[1] "Truth is not found"

for 循环

v <- LETTERS[1:4]
for ( i in v) {
   print(i)
}

[1] "A"
[1] "B"
[1] "C"
[1] "D"

while 循环

v <- c("Hello","while loop")
cnt <- 2

while (cnt < 7) {
   print(v)
   cnt = cnt + 1
}

[1] "Hello"  "while loop"
[1] "Hello"  "while loop"
[1] "Hello"  "while loop"
[1] "Hello"  "while loop"
[1] "Hello"  "while loop"

repeat 循环

v <- c("Hello","loop")
cnt <- 2

repeat {
   print(v)
   cnt <- cnt+1
   
   if(cnt > 5) {
      break
   }
}

[1] "Hello" "loop" 
[1] "Hello" "loop" 
[1] "Hello" "loop" 
[1] "Hello" "loop"

函数

内置函数的简单示例是seq()，mean()，max()，sum(x)和paste(…)等

# Create a sequence of numbers from 32 to 44.
print(seq(32,44))

# Find mean of numbers from 25 to 82.
print(mean(25:82))

# Find sum of numbers frm 41 to 68.
print(sum(41:68))

[1] 32 33 34 35 36 37 38 39 40 41 42 43 44
[1] 53.5
[1] 1526

用户定义的函数

# Create a function to print squares of numbers in sequence.
new.function <- function(a) {
   for(i in 1:a) {
      b <- i^2
      print(b)
   }
}

# Call the function new.function supplying 6 as an argument.
new.function(6)


[1] 1
[1] 4
[1] 9
[1] 16
[1] 25
[1] 36

R语言基本语法（中）

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