如何提取包含在“$”和“/”（特殊字符）之间的子字符串，然后替换该子字符串的值？

Question

我将主字符串作为 str 和需要命名为 su_str:

的子字符串

su_str = "$Region_Name" ,

str <- " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name/Billing/report.csv"

和 $Region_Name = ap-southeast-1 的值在其他文件中。

我试过了：

r <- unlist(stri_extract_all(p,"$ /"))

它会给出如下错误：

Error in stri_extract_all(p, "$ /") : you have to specify either regex, fixed, coll, or charclass

c_prop 将是：
键：值
$导演姓名：DF-1C
$DirectorPortName : 端口，DF-1C
$掩蔽视图名称：000197801199，IS_LGLW9062_VIEW
$MaskingInitiatorPortName：启动器端口，IS_LGLW9062_VIEW
$MaskingAssDeviceName :关联设备，IS_LGLW9062_VIEW
$池名称：000197801199，SRP_1
$PoolBoundDevice : 绑定设备，SRP_1
$端口名称：DF-1C:12
$Region_Name : ap-东南-1

如何解决这个问题，给点思路？提前致谢！！！

Answer 1

这适用于您的示例，是否解决了您的问题？使用正则表达式（或正则表达式）时，必须使用两个反斜杠 \ 转义 R 中的特殊字符。看起来使用 stringi 替换也必须转义特殊字符，但我不经常使用 stringi 所以希望有人可以使用 stringi

> library(stringi)
> 
> str <- " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name/Billing/report.csv"
> 
> # If you just want to extract the sequence of letters and underscores's after "$" and before the "/"
> unlist(stri_extract_all(str, regex = "\$[[:alpha:]_]*\b"))
[1] "$Region_Name"
> 
> # If you want to replace it with something else using base R
> 
> some_string <- "$Region_Name = ap-southeast-1"
> 
> gsub("\$[[:alpha:]_]*\b", some_string, str)
[1] " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name = ap-southeast-1/Billing/report.csv"
> 
> # Using stringi package
> 
> # Special characters have to be escaped
> some_string <- "\$Region_Name \= ap\-southeast\-1"
> 
> stri_replace_all(str, some_string, regex = "\$[[:alpha:]_]*\b")
[1] " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name = ap-southeast-1/"

编辑：如果你想对同一个子字符串进行多次替换：

# If the substring will always be "$Region_Name"

su_str <- "$Region_Name"
replacements <- c("$Region_Name = ap-southeast-1/", "$Region_Name = ap-southeast-2/")

stri_replace_all(str, replacements, fixed = su_str)
[1] " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name = ap-southeast-1//Billing/report.csv"
[2] " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name = ap-southeast-2//Billing/report.csv"

Answer 2

您的问题标题和您要问的问题是两个不同的问题，但我会尝试同时解决这两个问题。

关于您在 stri_extract_all() 中遇到的错误，您需要指定要匹配的模式类型，我相信您正在尝试匹配固定模式，在这种情况下您可以使用

stri_extract_all_fixed()

函数代替。

但是我不使用 stri_extract_all() 来删除和替换您的 sub-string。这是我的解决方案。

str <- " https://lglbw.pqr.xyz.com:58443/APG/lookup/All/Report%20Library/Amazon%20S3/Inventory/Regions/$Region_Name/Billing/report.csv"
reg<-"$Region_Name"
replce<-"ap-southeast-1"

# Custom function to return position of a sub string 
strpos_fixed<-function(x,y){
  a<-regexpr(y, x,fixed=T)
  b<-a[1]
  return(b)
}

part1<-substr(str,1,(strpos_fixed(str,reg)-1))
part2<-substr(str,(strpos_fixed(str,reg)+nchar(reg)),nchar(str))

part1 # Everything before "$Region_Name"
part2 # Everything after  "$Region_Name"

new<-paste(part1,replce,part2, sep ="")
new

如何提取包含在“$”和“/”（特殊字符）之间的子字符串，然后替换该子字符串的值？

how to extract the sub-string which is enclosed in between '$' and '/' (special characters) and then substitute the value of that sub-string?

string

r

extract

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