CODEWITHSUNDEEP
regexstringjulia
RikH
RikH

Reputation: 3404

How to evaluate functions substituted by a regex in Julia?

Say I got a (possibly long) string containing matches for some regex. I would like to be able to call a non-trivial Julia function on all the matches and substitute the output in the string.

For example, let the regex be \|[0-9]+\| and the computation function be f(x) = x^2.

This is a string containing |1| and |4|.

I would like to obtain as a result

This is a string containing 1 and 16.

My question is: how can I implement this? Note that it would be nice if the code works for different regular expressions.

Upvotes: 2

Views: 241

Answers (1)

Bogumił Kamiński
Bogumił Kamiński

Reputation: 69829

Just use the replace function:

julia> s = "This is a string containing |1| and |4|."
"This is a string containing |1| and |4|."

julia> replace(s, r"\|[0-9]+\|" => x -> parse(Int, chop(x,  head=1, tail=1)) ^ 2)
"This is a string containing 1 and 16."

In general in the signature of replace that has the form:

replace(s::AbstractString, pat=>r; [count::Integer])

note that pat can be a Regex, and r can be a function taking the match as an argument.

Upvotes: 4

Related Questions