R-函数/语法-整合版

函数名	功能	例子	例子效果
print()	打印	print ( "hello world")	"hello world"
c()	把多个向量拼成数组	apple<-c("red","green"); print(apple); print(class(apple))	[1] "red" "green" [1] "character"
list()	组合出列表变量	list1<-list(c(2,5,3),21.3,sin); print(list1)	[[1]] [1] 2 5 3 [[2]] [1] 21.3 [[3]] function (x) .Primitive("sin")
matrix()	生成 矩阵型 变量	M=matrix(c('a','a','b'),nrow=2,ncol=3,byrow=TRUE); print(M)	[,1] [,2] [,3] [1,] "a" "a" "b"  [2,] "a" "a" "b"
if() {}	决策	x<-30L; if(is.integer(x)) {print("X is an Integer") }	"X is an Integer"
if() {} else {}	决策
if ... else if ... else	决策
switch(exp , case1, case2, case3...)	决策	x<-switch(3,"one","two","three"); print(x)	"three"
repeat { commands if(condition) { break } }	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"
while	一次又一次地执行相同的代码，直到满足停止条件 while (exp) { statement }	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"
for	for (exp) { statement }	v <- LETTERS[1:4]; for ( i in v) { print(i) }	[1] "A" [1] "B" [1] "C" [1] "D"
cbind()	连接多个向量，每个向量为一列	city <- c("Tampa","Seattle","Hartford","Denver") state <- c("FL","WA","CT","CO") zipcode <- c(33602,98104,06161,80294) addresses <- cbind(city,state,zipcode); print(address)	city    state   zipcode [1,] "Tampa" "FL" "33602" [2,] "Seattle" "WA" "98104" [3,] "Hartford" "CT" "6161" [4,] "Denver" "CO" "80294"
rbind()	上下合并两个数据帧 (类似 sql 的union all)	city <- c("Tampa","Seattle","Hartford","Denver") state <- c("FL","WA","CT","CO") zipcode <- c(33602,98104,06161,80294) all.addresses <- rbind(addresses,addresses); print(all.addresses)	city    state  zipcode [1,] "Tampa" "FL" "33602" [2,] "Seattle" "WA" "98104" [3,] "Hartford" "CT" "6161" [4,] "Denver" "CO" "80294" [5,] "Tampa" "FL" "33602" [6,] "Seattle" "WA" "98104" [7,] "Hartford" "CT" "6161" [8,] "Denver" "CO" "80294"
merge()	合并两个数据帧，数据帧必须具有相同的列名，在其上进行合并