str_split(x," ")根据字符串内" "(空格)进行拆分class(str_split(x," "))1 "list"#获得向量:[1]#str_split()可对多个字符串进行拆分,每个字符串成为一个数据框...(x," |,") #按" "或","进行拆分1.3 按位置提取字符str_sub(x,5,9)1 "birch"#提取第5到第9个字符1.4 字符检测str_detect(x2,"h")对每个字符串内的字符进行检测...test$Sepal.Width#该语句运行完数据框列数即增加无需赋值2.4 筛选列、行select() #筛选列filter() #筛选行2.5 管道符号x1 = select(iris,-5)...多个条件仍适用if(){code1}else if(){code2}else{code3}3.2 ifelse函数仅有三个参数ifelse(x,yes,no)#x:逻辑值或逻辑值向量#yes:逻辑值为T时的返回值...#no:逻辑值为F时的返回值i = 1ifelse(i>0,"+","-")1 "+"多个条件仍适用ifelse(i>0,"+",ifelse(i<0,"-","0"))3.3 ifelse() + str_detect