Is there a single quantifier for matching exactly n or m occurrences of a pattern in regex?

Matching Exactly n or m Occurrences with Regex

The regular expression X{n}|X{m} allows for a pattern X to occur either n or m times. However, some users may seek a more convenient quantifier to represent this construct.

Question:

Is there a specific quantifier that tests for an occurrence of X exactly n or m times?

Answer:

While there isn't a single quantifier that serves this exact purpose, the provided approach is valid. Alternatively, the following regex can also be used:

X{m}(X{k})?

where:

• m is less than n.
• k is n - m.

This alternative expression matches X exactly m times followed by optional additional occurrences (up to k times) of X, effectively testing for either n or m occurrences of X.

The above is the detailed content of Is there a single quantifier for matching exactly n or m occurrences of a pattern in regex?. For more information, please follow other related articles on the PHP Chinese website!