I am trying to match below paterns:

A-Test!1.2
A-Test
ATest
A-Test!1.2.3

in below text:

 [A-Test!1.2]    [xyz]      [def]
 [A-Test]    [xyz]      [def]
 [ATest]    [xyz]      [def]
 [A-Test!1.2.3]    [xyz]      [def]

I tried my hand @ regex

[^\[] (\-*\!\d.\d(?:.\d))

But it is only matching one line:

Can you please guide on how to get the matches done for all lines?

CodePudding user response：

Use ? for optional pattern

I assume the difference between the [] boxes is the searched string must start with a capital letter, and the part from ! onwards is optional. You can make something optional with a ? behind it.

You can use this regular expression to find your example texts:

\[([A-Z][A-Za-z0-9-] (![\d.] )?)\]

See here to play around with it:
https://regex101.com/r/5ekTkJ/1

CodePudding user response：

You may spell out all the pattern parts, e.g. like

(?<=\[)[A-Z]-?[A-Za-z] (?:!\d (?:\.\d )*)?(?=])

See the regex demo. Details:

• (?<=\[) - a positive lookbehind that requires a [ char immediately on the left
• [A-Z] - an uppercase letter
• -? - an optional -
• [A-Za-z] - one or more letters
• (?:!\d (?:\.\d )*)? - an optional group matching
  • ! - a ! char
  • \d (?:\.\d )* - one or more digits and then zero or more occurrences of . and one or more digits
• (?=]) - a positive lookahead that requires a ] char immediately on the right.