R:具有多个正则表达式模式和异常的拆分文本

Question

想text在句子中分割出一个字符元素的向量.分裂标准有多种模式("and/ERT","/$").也有例外(:/$.,and/ERT then,./$. Smiley)自该模式.

尝试:匹配拆分应该的情况."^&*"在该位置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.有明确的情况"^&*"应该消除异常模式()并在运行之前恢复原始文本strsplit.

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

我想你可以使用这个表达式来获得你想要的分裂.当strsplit用完它分割的字符时,你必须在要匹配的东西之后的空格上分开/不匹配(这是你在OP中所需输出中所拥有的):

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 !/$."      
#[8] "Thank you ./$!" 

说明

• (?<=and/ERT)\\s -上的空间分割,\\s即IS之前,(?<=...)通过"and/ERT"
• (?!then) - 但是,如果没有遵循该空间,请(?!...)通过"then"
• | - OR运算符链接下一个表达式
• (?<=/\\$[[:punct:]]) - 积极的后视断言,"/$"随后是任何标点符号
• (?<!:/\\$[[:punct:]])\\s(?!Smiley)-匹配在一个空间NOT前面加上":/$"[[:punct:]]根据前一个点(但IS由前面"/$[[:punct:]]"但NOT接着,(?!...)通过"Smiley"