R语言 字符串切割

1. strsplit {base}

语法：

strsplit(x, split, fixed = FALSE, perl = FALSE, useBytes = FALSE)

参数：x待切割的字符串；split分割符。
备注：返回值为list。

示例：

strsplit("a.b.c", ".", fixed = TRUE)
[[1]]
[1] "a" "b" "c"

---

2. str_split {stringr}

语法：

str_split(string, pattern, n = Inf, simplify = FALSE)
str_split_fixed(string, pattern, n) ##与str_split参数simplify为TRUE效果一致

参数：string待切割的字符串；pattern分割符；n切割为多少列；simplify如果为FALSE，返回值为字符串向量的list，如果为TRUE，返回值为字符串矩阵的list。

示例：

library("stringr")

fruits <- c(
+     "apples and oranges and pears and bananas",
+     "pineapples and mangos and guavas"
+ )

str_split(fruits, " and ")
[[1]]
[1] "apples"  "oranges" "pears"   "bananas"

[[2]]
[1] "pineapples" "mangos"     "guavas"    

## simplify的作用
str_split(fruits, " and ", simplify = TRUE)
     [,1]         [,2]      [,3]     [,4]     
[1,] "apples"     "oranges" "pears"  "bananas"
[2,] "pineapples" "mangos"  "guavas" ""       
## n的作用
str_split(fruits, " and ", n = 3)
[[1]]
[1] "apples"            "oranges"           "pears and bananas"

[[2]]
[1] "pineapples" "mangos"     "guavas"    

str_split(fruits, " and ", n = 3, simplify = TRUE)
     [,1]         [,2]      [,3]               
[1,] "apples"     "oranges" "pears and bananas"
[2,] "pineapples" "mangos"  "guavas" 

str_split_fixed(fruits, " and ", 3)  ##与str_split(fruits, " and ", n = 3, simplify = TRUE)效果一致
     [,1]         [,2]      [,3]               
[1,] "apples"     "oranges" "pears and bananas"
[2,] "pineapples" "mangos"  "guavas"