R:带有多个正则表达式模式和异常的拆分文本

Question

想要在句子中拆分字符元素text的向量。有一个更多的分裂标准模式("and/ERT"，"/$")。此外，模式也有例外(:/$.、and/ERT then、./$. Smiley)。

尝试:匹配应该分割的情况。在那个地方插入一个不寻常的图案("^&*")。strsplit特定模式

问题:我不知道如何正确处理异常。在运行"^&*"之前，应该消除异常模式( strsplit )并恢复原始文本，这是非常明显的情况。

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

我想你可以用这个表达式来达到你想要的分裂。由于strsplit用光了它在上面拆分的字符，您将不得不在空格上拆分，下面是要匹配/不匹配的内容(这是OP中所需输出中的内容)：

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 -在空格上拆分，\\s，IS，(?<=...) by "and/ERT"
• (?!then) -，但只有当那个空格是而不是，(?!...)是"then"
• | - OR运算符链接下一个表达式
• (?<=/\\$[[:punct:]]) - "/$"的正面后视断言，后面跟着任何标点符号
• (?<!:/\\$[[:punct:]])\\s(?!Smiley) -匹配一个空格，即，而不是，前面是":/$"[[:punct:]] (但是根据前面的点，是，前面是"/$[[:punct:]]"，不是，(?!...)后面是"Smiley"