I'm trying to find a solution to a regex that can match anything after a string or nothing, but if there's something it can't be a dot .

is it possible to do without negative lookahead?

here's an example regex:

.*\.(cpl)[^.].*

now the string:

C:\Windows\SysWOW64\control.exe mlcfg32.cpl sounds

this one is matched, but if there's only:

C:\Windows\SysWOW64\control.exe mlcfg32.cpl

it's not matched because due to the dot blacklist it's searching for any character after cpl,if i use ? after the [^.] however it won't blacklist the . in case there's something else after, so it will capture this even if it shouldn't:

C:\Windows\SysWOW64\control.exe mlcfg32.cpl. sounds

can it be done without using negative lookaheads? - ?!

CodePudding user response：

You may use this regex:

.*\.cpl(?:[^.].*|$)

RegEx Demo

RegEx Breakdown:

• .*: Match 0 or more of any character
• \.cpl: Match .cpl
• (?:[^.].*|$): Match end of string or a non-dot followed by any text

CodePudding user response：

You can use

.*\.(cpl)(?:[^.].*)?$

See the regex demo. Details:

• .* - zero or more chars other than line break chars as many as possible
• \. - a dot
• (cpl) - Group 1: cpl
• (?:[^.].*)? - an optional non-capturing group that matches a char other than . char and then zero or more chars other than line break chars as many as possible
• $ - end of string.