How to precisely identify & work greedy or reluctant quantifiers?

2018-06-04 01:21:06

This question already has an answer here:

SCJP6 regex issue 1 answer

These are the matches of d* against "ab34ef" :

index 0: zero-width;

index 1: zero-width;

index 2: "34";

index 4: zero-width;

index 5: zero-width;

index 6: zero-width.

This should explain your output. If the quantifier was reluctant, this would be the difference:

index 2: zero-width;

index 3: zero-width;

The reluctant quantifier grabs as little as allowed to make the entire expression match.

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