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

I have the main string as str and substring which is required named as su_str:

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"

and the value of $Region_Name = ap-southeast-1 that is in some other file.

I tried : 

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

and it will give an error like:

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

c_prop will be:
Key: Value
$DirectorName : DF-1C
$DirectorPortName : Ports, DF-1C
$MaskingViewName : 000197801199, IS_LGLW9062_VIEW
$MaskingInitiatorPortName : Initiator Ports, IS_LGLW9062_VIEW
$MaskingAssDeviceName :Associated Devices, IS_LGLW9062_VIEW
$PoolName : 000197801199, SRP_1
$PoolBoundDevice : Bound Devices, SRP_1
$PortName : DF-1C:12
$Region_Name : ap-southeast-1
enter image description here

How to solve this issue, suggest some idea? Thanks in Advance!!!

Solution

  • This works for your example, does it solve your problem? When using regex (or regular expressions), you have to escape special characters in R with two backslashes \\. It looks like using stringi the replacement must have special characters escaped as well, but I do not use stringi often so hopefully someone can chime in on a better way to do it using 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/"

    EDIT: if you want a multiple replacements for the same substring:

    # 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"