Using *, + and similar on a capture doesn't make much sense, and therefore neither does the result. If you wished to capture the separator, you should have used 

@num = split /((?:a|b)+)/, $x;  # @num = ('12','aba','34','ba','5')

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In reply to Re: Regexp - groupings by ikegami
in thread Regexp - groupings by Anonymous Monk

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