CODEWITHSUNDEEP
javaregex
spacegoing
spacegoing

Reputation: 5306

Java Regex: How to match all patterns including overlapping regex matches?

Suppose I have a String NNNN.

The regex is N+N.

How to configure the matcher to let it return NNNN, NNN and NN since NNN and NN also match pattern N+N?

Upvotes: 1

Views: 414

Answers (1)

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89639

You need to enclose your pattern in a lookahead and a capture group:

(?=(N+N))

The results are in the group 1.

Since the lookahead is a zero-width assertion, characters are not consumed by the pattern and can be "reuse" for the next match (from the next position in the string).

N    N    N    N  
x______________^  # first match
     x_________^  # second match
          x____^  # third match

x____^ is the content of the capture group and x is the start position.

Upvotes: 5

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