I want to match the digits before h, m, and s into their respective capture groups. I want to match all 3 groups if possible. If one or two of the other groups are missing then match the last group(s).

As seen in the image below and in this

But I want 7 matches. Where the first match contains 3 groups, the 2:nd to 4:th match contain 2 groups each and the last 3 matches contain 1 group each.

So I want:

1. Match 1: 11h22m33s
   1. Group 1: 11
   2. Group 2: 22
   3. Group 3: 33
2. Match 2: 11h22m
   1. Group 1: 11
   2. Group 2: 22
3. Match 3: 11h33s
   1. Group 1: 11
   2. Group 2: 33
4. Match 4: 22m33s
   1. Group 1: 22
   2. Group 2: 33
5. Match 5: 11h
   1. Group 1: 11
6. Match 6: 22m
   1. Group 1: 22
7. Match 7: 33s
   1. Group 1: 33

Edit

The test strings can be contained within other strings! E.g. 08:00 11h. See https://regex101.com/r/RWA9Oy/1

CodePudding user response：

If you need to make sure the whole string matches the pattern, you can use

^(?!$)(?:(\d )h)?(?:(\d )m)?(?:(\d )s)?$

See the regex demo.

If you need to extract these strings from the longer texts, you can use

\b(?=\w)(?:(\d )h)?(?:(\d )m)?(?:(\d )s)?\b(?!\w)

See this regex demo.

Details:

• ^ - start of string
• (?!$) - the string can't end at the very start (=cannot be empty)
• \b(?=\w) - a word boundary where the char immediately on the right is a word char (=is a letter, digit or _)
• (?:(\d )h)? - an optional non-capturing group matching one or more digits (capturing them into Group 1) and a h letter
• (?:(\d )m)? - an optional non-capturing group matching one or more digits (capturing them into Group 2) and a m letter
• (?:(\d )s)? - an optional non-capturing group matching one or more digits (capturing them into Group 3) and a s letter
• $ - end of string
• \b(?!\w) - a word boundary where the char immediately on the right is NOT a word char or at the end of string.

Just in case you want allow any amount of whitespace between the components, you may add \s*:

^(?!\s*$)\s*(?:(\d )\s*h\s*)?(?:(\d )\s*m\s*)?(?:(\d )\s*s)?\s*$

Or, for partial matching

\b(?=\w)(?:(\d )\s*h\s*)?(?:(\d )\s*m\s*)?(?:(\d )\s*s)?\b(?!\w)

See this regex demo and another regex demo.