Extract part of string between two different patterns

Question

I try to use stringr package to extract part of a string, which is between two particular patterns.

For example, I have:

my.string <         


        

Answer 1

I do not know whether and how this is possible with functions provided by stringr but you can also use base regexpr and substring:

pattern <- paste0("(?<=", left.border, ")[a-z]+(?=", right.border, ")")
# "(?<=nana)[a-z]+(?=baba)"

rx <- regexpr(pattern, text=my.string, perl=TRUE)
# [1] 5
# attr(,"match.length")
# [1] 6

substring(my.string, rx, rx+attr(rx, "match.length")-1)
# [1] "qwerty"