假设我有一个字符串向量，例如
split_these = c("File Location:C:\\Documents","File Location:Pete's Computer","File Location:")
我想根据“：”分割该向量中的每个元素，除非后面有“\”。我想要的是返回类似的东西
#preferred solution
"File Location" "C:\\Documents"
"File Location" "Pete's Computer"
"File Location" ""
or
#less preferred but still great
"File Location" "C:\\Documents"
"File Location" "Pete's Computer"
"File Location"
我尝试过以下方法
strsplit(split_these, ":")
[[1]]
[1] "File Location" "C" "\\Documents"
[[2]]
[1] "File Location" "Pete Computer"
[[3]]
[1] "File Location"
strsplit(split_these, ":[^\\]")
[[1]]
[1] "File Location" ":\\Documents"
[[2]]
[1] "File Location" "ete Computer"
[[3]]
[1] "File Location:"
我建议将 PCRE 与否定的前瞻断言一起使用。另请注意，您需要对反斜杠进行双转义，因为它在 R 字符串和正则表达式语法中充当元字符。
strsplit(perl=T,split_these,':(?!\\\\)');
## [[1]]
## [1] "File Location" "C:\\Documents"
##
## [[2]]
## [1] "File Location" "Pete's Computer"
##
## [[3]]
## [1] "File Location"
如果您想将列表简化为单个字符向量：
do.call(c,strsplit(perl=T,split_these,':(?!\\\\)'));
## [1] "File Location" "C:\\Documents" "File Location" "Pete's Computer" "File Location"
我想出了一个办法来获取尾随的空字符串字段。自从strsplit()总是省略最后一个空字段，我们可以简单地将分隔符连接到每个输入字符串的末尾。如果原始字符串中没有尾随分隔符，则新的空字段将被省略，而不改变结果。如果有was原始字符串中的尾部分隔符，然后我们将得到我们想要的空字段：
do.call(c,strsplit(perl=T,paste0(split_these,':'),':(?!\\\\)'));
## [1] "File Location" "C:\\Documents" "File Location" "Pete's Computer" "File Location" ""
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