I am struggling for long time.
I manage to extract everything between my Right and Left patterns in a string as you can see in the following example.
library(tidyverse) data=c("everything will be ok one day") str_extract(string = data, pattern = "(?<=thing).*(?=ok one)") #>  " will be "
Created on 2022-01-26 by the reprex package (v2.0.1)
As you notice in the code, I extract everything between "thing" and "ok one".
I need to incorporate the possibility of mismatches inside these patterns.
I want to allow a maximum of two mismatches and consider indels and insertions.
This is just a simplified example. My actual data does not contain gaps, and it's complicated. I am looking forward to receiving your help and guidance.