kust like [*]

is just the format for the property control number on the Palm Beach County Florida

It won't capture in the group.we can't back refrence A(?:nt|pple)\sA\1

Find label in MIPS assembly

Match lines with CR (Carriege Return) with no LF (Line Feed - New Line) or PG (Page Break) next to it.

This regular expression will match an IPv4 address as well as both compressed or uncompressed IPv6 address.

Extract the server and database name from SQL Server connection string

This regexp is used in the SPIP cms for create tags fastly when you are writting a post.

Atomic Groups are non-capturing and once a match is made will exit the atomic group and throw away all backtracks. Use Atomic Groups for optimising performance. A non-atomic expression \b(foobar|foot|foo)\b and a test string of foots will: match foo of foobar => fail and backtrack to the 2nd alter...

Look ahead Positive(?=) Find expression A where expression B follows A(?=B) ...

Look ahead Positive(?=) Find expression A where expression B follows A(?=B) ...

Look ahead Positive(?=) Find expression A where expression B follows A(?=B) ...

finds the first bar (Find "bar" which has "bar" after it)