regex - R:使用多个正则表达式模式和异常拆分文本

Question

想要分割字符元素的向量 text在句子中。有不止一种拆分标准模式( "and/ERT" ， "/$" )。模式中也有异常(exception)( :/$. 、 and/ERT then 、 ./$. Smiley )。

尝试:匹配应该拆分的情况。在那个地方插入一个不寻常的图案 ( "^&*" )。 strsplit具体模式

问题:我不知道如何正确处理异常。有一些明确的情况，在运行 "^&*" 之前应该消除异常模式( strsplit )并恢复原始文本。 .

代码:

text <- c("This are faulty propositions one and/ERT two ,/$, which I want to split ./$. There are cases where I explicitly want and/ERT some where I don't want to split ./$. For example :/$. when there is an and/ERT then I don't want to split ./$. This is also one case where I dont't want to split ./$. Smiley !/$. Thank you ./$!",
"This are the same faulty propositions one and/ERT two ,/$, which I want to split ./$. There are cases where I explicitly want and/ERT some where I don't want to split ./$. For example :/$. when there is an and/ERT then I don't want to split ./$. This is also one case where I dont't want to split ./$. Smiley !/$. Thank you ./$!",
"Like above the same faulty propositions one and/ERT two ,/$, which I want to split ./$. There are cases where I explicitly want and/ERT some where I don't want to split ./$. For example :/$. when there is an and/ERT then I don't want to split ./$. This is also one case where I dont't want to split ./$. Smiley !/$. Thank you ./$!")

patternSplit <- c("and/ERT", "/\\$") # The class of split-cases is much larger then in this example. Therefore it is not possible to adress them explicitly.
patternSplit <- paste("(", paste(patternSplit, collapse = "|"), ")", sep = "")

exceptionsSplit <- c("\\:/\\$\\.", "and/ERT then", "\\./\\$\\. Smiley")
exceptionsSplit <- paste("(", paste(exceptionsSplit, collapse = "|"), ")", sep = "")

# If you don't have exceptions, it works here. Unfortunately it splits "*$/*" into "*" and "$/*". Would be convenient to avoid this. See example "ideal" split below.
textsplitted <- strsplit(gsub(patternSplit, "^&*\\1", text), "^&*", fixed = TRUE) # 

# Ideal split:
textsplitted
> textsplitted
[[1]]
 [1] "This are faulty propositions one and/ERT" 
 [2] "two ,/$," 
 [3] "which I want to split ./$."
 [4] "There are cases where I explicitly want and/ERT" 
 [5] "some where I don't want to split ./$." 
 [6] "For example :/$. when there is an and/ERT then I don't want to split ./$."
 [7] "This is also one case where I dont't want to split ./$. Smiley !/$." 
 [8] "Thank you ./$!"

[[2]]
 [1] "This are the same faulty propositions one and/ERT 
 [2] "two ,/$,"
#...      

# This try doesen't work!
text <- gsub(patternSplit, "^&*\\1", text)
text <- gsub(exceptionsSplit, "[original text without "^&*"]", text)
textsplitted <- strsplit(text, "^&*", fixed = TRUE)

Answer 1

我认为您可以使用此表达式来实现您想要的拆分。如 strsplit用完它拆分的字符，您将不得不在要匹配/不匹配的事物后面的空格上拆分(这是您在 OP 中所需的输出中所拥有的):

strsplit( text[[1]] , "(?<=and/ERT)\\s(?!then)|(?<=/\\$[[:punct:]])(?<!:/\\$[[:punct:]])\\s(?!Smiley)"  , perl = TRUE )
#[[1]]
#[1] "This are faulty propositions one and/ERT"                                 
#[2] "two ,/$,"                                                                 
#[3] "which I want to split ./$."                                               
#[4] "There are cases where I explicitly want and/ERT"                          
#[5] "some where I don't want to split ./$."                                    
#[6] "For example :/$. when there is an and/ERT then I don't want to split ./$."
#[7] "This is also one case where I dont't want to split ./$. Smiley !/$."      
#[8] "Thank you ./$!" 

解释

(?<=and/ERT)\\s - 在空格上分割，\\s那个 IS 之前，(?<=...)来自 "and/ERT"

(?!then) - 但是 仅当该空间为 不是 关注，(?!...)来自 "then"

| - OR 运算符链接下一个表达式

(?<=/\\$[[:punct:]]) - "/$" 的正向后视断言后跟任何标点字母

(?<!:/\\$[[:punct:]])\\s(?!Smiley) - 匹配一个空格 不是 前面是 ":/$"[[:punct:]] (但根据前一点 IS 前面是 "/$[[:punct:]]" 但 NOT 后面是 (?!...) 由 "Smiley"7 |108