R语言strsplit函数用法

1、R语言strsplit用于分割字符串

    创建测试数据

> test <- "aa bb cc dd ee ff"  ##创建测试数据
> test
[1] "aa bb cc dd ee ff"
> class(test)  ## 测试数据为字符
[1] "character"

2、按照指定分隔符拆分字符串

> a <- strsplit(test,split = " ") ##制动分隔符为空格进行拆分数据
> a
[[1]]
[1] "aa" "bb" "cc" "dd" "ee" "ff"

> class(a)  ## 分割后的数据类型为列表
[1] "list"

> b <- strsplit(test,split = "")  ## 分隔符设为空，则拆分每一个字符
> b
[[1]]
 [1] "a" "a" " " "b" "b" " " "c" "c" " " "d" "d" " " "e" "e" " " "f"
[17] "f"

> test <- "aa,bb,cc,dd,ee!ff!GG" ##重新创建测试数据
> strsplit(test,split = ",")  ##指定分隔符为","进行拆分
[[1]]
[1] "aa"       "bb"       "cc"       "dd"       "ee!ff!GG"

> strsplit(test,split = "!") ##指定分隔符为"!"进行拆分
[[1]]
[1] "aa,bb,cc,dd,ee" "ff"             "GG"            

> test <- "aa\\sbb\\scc\\sdd\\see\\sff"  ##重新创建测试数据
> strsplit(test,split = "\\s")  ##指定分隔符"\\s"进行拆分，未起作用
[[1]]
[1] "aa\\sbb\\scc\\sdd\\see\\sff"

> strsplit(test,split = "\\s",fixed = T) ##设置fixed = T,正常拆分，参数作用为精确匹配，屏蔽正则表达式
[[1]]
[1] "aa" "bb" "cc" "dd" "ee" "ff"

> test <- "aa.bb.cc.dd.ee"     ##同上
> strsplit(test,split = ".")
[[1]]
 [1] "" "" "" "" "" "" "" "" "" "" "" "" "" ""

> strsplit(test,split = ".",fixed = T)
[[1]]
[1] "aa" "bb" "cc" "dd" "ee"

3、指定输出结果为向量 

> test <- "aa,bb,cc,dd,ee" ##生产测试数据
> a <- strsplit(test,split = ",") 
> a
[[1]]
[1] "aa" "bb" "cc" "dd" "ee"

> class(a)
[1] "list"
> b <- unlist(strsplit(test,split = ","))  ## 加unlist函数
> b
[1] "aa" "bb" "cc" "dd" "ee"
> class(b)   
[1] "character"