Regex 拆分stringr中大写字母紧跟小写字母的字符串

我有一个字符串向量，看起来像这样，我想把它分开：

str <- c("Fruit LoopsJalapeno Sandwich", "Red Bagel", "Basil LeafBarbeque SauceFried Beef")

str_split(str, '[a-z][A-Z]', n = 3)

[[1]]
[1] "Fruit Loop"       "alapeno Sandwich"

[[2]]
[1] "Red Bagel"

[[3]]
[1] "Basil Lea"    "arbeque Sauc" "ried Beef"

---

str这里是base中的两种方法（如果需要，您可以推广到stringr）

这一个用占位符把这个地方划出，然后在那个地方分开

strsplit(gsub("([a-z])([A-Z])", "\\1SPLITHERE\\2", str), "SPLITHERE")

## [[1]]
## [1] "Fruit Loops"       "Jalapeno Sandwich"
## 
## [[2]]
## [1] "Red Bagel"
## 
## [[3]]
## [1] "Basil Leaf"     "Barbeque Sauce" "Fried Beef"  

此方法使用lookaheads和lookbehinds：

strsplit(str, "(?<=[a-z])(?=[A-Z])", perl=TRUE)

## [[1]]
## [1] "Fruit Loops"       "Jalapeno Sandwich"
## 
## [[2]]
## [1] "Red Bagel"
## 
## [[3]]
## [1] "Basil Leaf"     "Barbeque Sauce" "Fried Beef"  

您还可以根据字符串进行匹配，而不是拆分

unlist(regmatches(str, gregexpr('[A-Z][a-z]+ [A-Z][a-z]+', str)))
# [1] "Fruit Loops"       "Jalapeno Sandwich" "Red Bagel"        
# [4] "Basil Leaf"        "Barbeque Sauce"    "Fried Beef" 

不错，可能更高效+1
unlist(regmatches(str, gregexpr('[A-Z][a-z]+ [A-Z][a-z]+', str)))
# [1] "Fruit Loops"       "Jalapeno Sandwich" "Red Bagel"        
# [4] "Basil Leaf"        "Barbeque Sauce"    "Fried Beef"