Question

我最近实现了一个函数来转义可解释为正则表达式的字符，这些正则表达式用于我的R包的系统调用＆＃39; rNOMADS＆＃39;

SanitizeWGrib2Inputs <- function(check.strs) {
    #Escape regex characters before inputting to wgrib2
    #INPUTS
    #    CHECK.STRS - Strings possibly containing regex metacharacters
    #OUTPUTS
    #    CHECKED.STRS - Strings with metacharacters appropriately escaped

    meta.chars <- paste0("\\", c("(", ")", ".", "+", "*", "^", "$", "?", "[", "]", "|"))

   for(k in 1:length(meta.chars)) {
       check.strs <- stringr::str_replace(check.strs, meta.chars[k], paste0("\\\\", meta.chars[k]))
   }

   checked.strs <- check.strs

   return(checked.strs)
}

我在我的包文档中包含了一个示例：

check.strs <- c("frank", "je.rry", "har\\old", "Johnny Ca$h")
checked.strs <- SanitizeWGrib2Inputs(check.strs)

这在我的ubuntu机器上正常工作并通过了CRAN检查。但是，当我将软件包上传到CRAN时，他们的Windows检查器说：

> check.strs <- c("frank", "je.rry", "har\\old", "Johnny Ca$h")
> checked.strs <- SanitizeWGrib2Inputs(check.strs) Error in stri_replace_first_regex(string, pattern, fix_replacement(replacement),  :    Invalid capture group name. (U_REGEX_INVALID_CAPTURE_GROUP_NAME) Calls: SanitizeWGrib2Inputs -> <Anonymous> -> stri_replace_first_regex -> .Call Execution halted
** running examples for arch 'x64' ... ERROR Running examples in 'rNOMADS-Ex.R' failed The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: SanitizeWGrib2Inputs
> ### Title: Make sure regex metacharacters are properly escaped
> ### Aliases: SanitizeWGrib2Inputs
> ### Keywords: internal
> 
> ### ** Examples
> 
> 
> check.strs <- c("frank", "je.rry", "har\\old", "Johnny Ca$h")
> checked.strs <- SanitizeWGrib2Inputs(check.strs) Error in stri_replace_first_regex(string, pattern, fix_replacement(replacement),  :    Invalid capture group name. (U_REGEX_INVALID_CAPTURE_GROUP_NAME) Calls: SanitizeWGrib2Inputs -> <Anonymous> -> stri_replace_first_regex -> .Call Execution halted

我在Windows分区上验证了此行为。为此做了什么工作？

Answer 1

使用简单的str_replace_all来转义所有特殊的正则表达式元字符：

SanitizeWGrib2Inputs <- function(check.strs) {
    return(str_replace_all(check.strs, "[{\\[()|?$^*+.\\\\]", "\\$0"))
}
check.strs <- c("frank", "je.rry", "har\\old", "Johnny Ca$h")
checked.strs <- SanitizeWGrib2Inputs(check.strs) 
checked.strs
## => [1] "frank"         "je\\.rry"      "har\\\\old"    "Johnny Ca\\$h"

备注：

"[{\\[\\]()|?$^*+.\\\\]（实际上，"[{\[\]()|?$^*+.\\]）将匹配任何单个字符，{，[，]，(，{ {1}}，)，|，?，$，^，*，+或{{1 }}

.替换会将每个字符更改为\ +相同的字符（"\\$0"是对整个匹配值的反向引用）。

我认为您不需要在此处添加\，因为如果前面没有配对的开放$0，则在字符类之外它不是特殊字符。

尝试在Windows上转义正则表达式字符时出现U_REGEX_INVALID_CAPTURE_GROUP_NAME错误

1 个答案: