Replace Whitespace before Brackets

Question

I'm trying to learn regular expressions and I would like all whitespaces before the open parenthesis to be replaced with an underscore using Notepad++ regular expression search and replace.

Currently, my regular expression only replaces a space if it is immediately before the open parenthesis.

Before: FIRST MIDDLE LAST(" ", " ")

Expected: FIRST_MIDDLE_LAST(" ", " ")

My attempted regular expression: \s+(?=\()

\s+ matches one or more white spaces (?=\() is a positive look ahead using \( (open parenthesis) as the character.

Can anyone please explain what the correct regular expression should be? Thanks in advance!

Answer 1

If I understood it correctly this should work for you:

Find \b\s+(?=.*?\() Replace: _

ie. all whitespaces following a word boundary, which is again followed by, but not a part of the selection, a couple of characters until the first occurrence of a opening bracket.