zero-width positive "look-behind"?

[Nathan]

"tttttattttt".match(/ttt(?=a)/) # http://rubular.com/r/21Zo6JP09f
=> ["ttt"]

"tttttattttt".match(/(?=a)ttt/) # http://rubular.com/r/d1VSUwwZUu

=> nil

Why? And how can I get this effect?

 

[Robert Klemme]

"tttttattttt".match(/ttt(?=a)/) # http://rubular.com/r/21Zo6JP09f => ["ttt"]
"tttttattttt".match(/(?=a)ttt/) # http://rubular.com/r/d1VSUwwZUu

=> nil

Why? And how can I get this effect?

It seems you have just demonstrated how to get the effect you described.

For more info:

http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt

Note: you need Ruby 1.9.

Kind regards

robert

 

[Nathan]

Ah (?<=3Da)ttt is what I was after. Thanks for the link.

"tttttattttt".match(/ttt(?=3Da)/) #http://rubular.com/r/21Zo6JP09f =3D> ["ttt"]
"tttttattttt".match(/(?=3Da)ttt/) #http://rubular.com/r/d1VSUwwZUu

=3D> nil

Why? And how can I get this effect?

It seems you have just demonstrated how to get the effect you described.

For more info:

http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt

Note: you need Ruby 1.9.

Kind regards

=A0 =A0 =A0 =A0 robert

ractices.com/