paste函数（用于字符串的连接等）

（1）两个元素进行连接

> paste("aa","bb",sep=",")

[1] "aa,bb"

paste("A",1:6,sep="")

[1] "A1" "A2" "A3" "A4" "A5" "A6"

(2)连接后变为一个字符串而不是多个元素（使用collapse参数）

a<-c("I1","I2","I7")

> a

[1] "I1" "I2" "I7"

> paste(a,collapse = ",")

[1] "I1,I2,I7"

（3）paste和cat区别

a<-1:3
> b<-4:6
> c<-c("ha","haha")
> paste(a,b,c)
[1] "1 4 ha" "2 5 haha" "3 6 ha"
> cat(a,b,c)
1 2 3 4 5 6 ha haha