m#<P>(?!.+<b>)(.+)</P>#i

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Nope. That would fail to match on a string like "<P>This is fine.</P><P><b>next</b></P>".

The next ought to work. It does a lookahead for the bad string "<b>" on every character it reconsiders matching, on the internal string. 

m#<P>(?:(?!<b>).)+?</P>#i

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In reply to Re^2: Regular expression matching by bart
in thread Regular expression matching by murugu

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