R语言中substr函数，字符串截取函数

1、测试1

x <- "dfserut"
x
substr(x,1,3)
substr(x,2,5)
substr(x,2)
substring(x,2)

 

2、测试2

x <- c("sfwsfs","ydsfs","gdsge","mhxsf")
x
substr(x,1,3)
substring(x,3)

 

 应用于向量

 

 

3、测试3

v1 <- c("sfde","fsdf","rere")
v2 <- c("erea","rftg","cfsd")
x <- data.frame(v1,v2)
x
substr(x$v1,1,2)
substring(x$v1,3)

 

应用于数据框 

 

4、测试4

x <- "dfserut"
x
substr(x,1,3)
substr(x,1,3) <- "ABC"
x
substr(x,1,3) <- "M"
x