R语言中字符串截取函数substr和substring 001、substr str <-"werewrt"## 测试字符串substr(str,1,3)## 提取1-3字符substr(str,3)## 必须指定起始substr(str,2,2)## 提取单个字符 002、substring str <-"werewrt"substring(str,1,4) substring(str,3)## 可以不指定末尾位置, 默认为字符串末尾substring...
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<-...
1、测试1 x <- "dfserut"x substr(x,1,3) substr(x,2,5) substr(x,2) substring(x,2) 1. 2. 3. 4. 5. 2、测试2 x <- c("sfwsfs","ydsfs","gdsge","mhxsf") x substr(x,1,3) substring(x,3) 1. 2. 3. 4. 应用于向量 3、测试3 v1 <- c("sfde","fsdf","rere") ...