Re[6]: [PHP] preg_replace: avoiding double replacements

Ash, Actually it's not the Caesar cypher itself (see http://en.wikipedia.org/wiki/Temurah_(Kabbalah), third method), but your way of transformation seems to me the best for a while) Thanks! -- With best regards from Ukraine, Andre Skype: Francophile; Wlm&MSN: arthaelon @ yandex.ru; Jabber: arthaelon @ jabber.org Yahoo! messenger: andre.polykanine; ICQ: 191749952 Twitter: m_elensule ----- Original message ----- From: Ashley Sheridan <ash@ashleysheridan.co.uk> To: Peter Lind <peter.e.lind@gmail.com> Date: Tuesday, May 18, 2010, 2:32:11 PM Subject: [PHP] preg_replace: avoiding double replacements On Tue, 2010-05-18 at 13:09 +0200, Peter Lind wrote: > On 18 May 2010 12:35, Andre Polykanine <andre@oire.org> wrote: > > Hello Peter, > > > > Hm... I see I need to specify what I'm really doing. Actually, I need > > to change the letters in the text. It's a famous and ancient crypting > > method: you divide the alphabet making two parts, then you change the > > letters of one part with letters for other part (so A becomes N, B > > becomes O, etc., and vice versa). it works fine and slightly with > > strtr or str_replace... but only if the text is not in utf-8 and it > > doesn't contain any non-English letters such as Cyrillic what I need. > > What my regex does is the following: it sees an A, well it changes it > > to N; then it goes through the string and sees an N... what does it > > do? Surely, it changes it back to A! I hoped (in vain) that there > > exists a modifier preventing this behavior... but it seems that it's > > false( > > Thanks! > > Hmmm, what comes to mind is using your string as an array and > translating one character after another, building your output string > using a lookup table. Not entirely sure how that will play with utf8 > characters, you'd have to try and see. > I don't think you'll get any of PHPs string functions to do the work > for you - they'll do the job in serial, not parallel. > > Regards > Peter > > -- > <hype> > WWW: http://plphp.dk / http://plind.dk > LinkedIn: http://www.linkedin.com/in/plind > Flickr: http://www.flickr.com/photos/fake51 > BeWelcome: Fake51 > Couchsurfing: Fake51 > </hype> > If you're wanting to use the Caesar cypher (for that's what it is) then why not just modify the entire string, character by character, to use a character code n characters ahead. For example, a capital A is ascii 65, you want to change it to an N to add 14 to that. Just keep n the same throughout and it's easy to convert back. Thanks, Ash http://www.ashleysheridan.co.uk