CODEWITHSUNDEEP
regex
Amit Goenka
Amit Goenka

Reputation: 106

Regex to match for all occurrences except when only one exists

I have this sample string 111:222:333. From this, I need to extract all three : separated numbers. The output should find three matches - 111 and 222 and 333.

I use this regex to achieve this: (?<=^|:)(\d+)(?=:|$).

However, I need this regex to match only when there are at least 2 matches. Hence, 111 should not match, but 111,222,... should.

I cannot use standard split functions in Java, because my use case mandates the regular expression being dynamically read from the database.

How do I enforce 'at least two matches' condition?

Upvotes: 1

Views: 194

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626794

You may use

(?<=\G(?!^):|^(?=\d+(?::\d+)+$))\d+

See the regex demo

Details

  • (?<=\G(?!^):|^(?=\d+(?::\d+)+$)) - a positive lookbehind that matches either of the two alternative locations in string:
    • \G(?!^): - a position after a previous successful match and :
    • | - or
    • ^(?=\d+(?::\d+)+$)) - start of a string that is followed with 1+ digits and then 1 or more sequences of : and 1+ digits up to the string end
  • \d+ - consuming 1 or more digits

Upvotes: 1

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