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Using regular expressions, is it possible to match a number of characters corresponding to the length of a previously captured group ?

I would like to match the following :

SomeLengthyPattern :
some_stuff         :
some_other_stuff   :

My idea was capturing SomeLengthyPattern and then using its length as a base to match some_stuff and some_other_stuff.

zx81
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DaLynX
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1 Answers1

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Surprisingly... Yes!

With a handful or regex engines, you can make sure that one token is matched the same number of times as a previous token.

  • In .NET, you can do it with balancing groups.
  • In PCRE and a few other, you can use what is known on this site as the Qtax trick. The requirement is that a capture Group must be able to contain a back-reference refer to itself.

Warning! These techniques are advanced. If you proceed further, your regex skills will improve tremendously.

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