How to inset dash between regex match?

Question

I need to add - in between of regex match in text file. I tried this but no luck!

-L\d{1,2} # this match all I need

Sa-L1
Sa-L23

Desire output:

Sa-L-1
Sa-L-23

There are -L in the lines, but I want to change -L with digits.

Use `-L(?=\d{1,2})` instead and replace it with `-L-`. This makes sure the numbers are there but excludes them from the match so they don't get replaced. Also this question is off-topic since it has nothing to do with programming. — Jesse, Feb 23 '22 at 18:03
Super. Thanks. Solved the problem. There are other numbers alone too like -1 so the target is -L[d]. But you solution worked! — izoysh, Feb 23 '22 at 18:04
You could replace zero-width matches of `(?<=-L)(?=\d+\b)` with a hyphen. [Demo](https://regex101.com/r/KkLMqI/1). There's no need to delete your question. Others reading it may find it useful even if there are no answers. — Cary Swoveland, Feb 23 '22 at 19:37

score 0 · Answer 1 · answered Feb 23 '22 at 23:10

Use

(-L)(\d)

Replace with $1-$2 or \1-\2.

See regex proof.

EXPLANATION

--------------------------------------------------------------------------------
  (                        group and capture to \1:
--------------------------------------------------------------------------------
    -L                       '-L'
--------------------------------------------------------------------------------
  )                        end of \1
--------------------------------------------------------------------------------
  (                        group and capture to \2:
--------------------------------------------------------------------------------
    \d                       digits (0-9)
--------------------------------------------------------------------------------
  )                        end of \2

How to inset dash between regex match?

1 Answers1