grum Posted March 26, 2006 Share Posted March 26, 2006 Hi guys,I hope everyone is well. Regex. Not my strong point. Any pointers appreciated.[code]$temp = preg_replace("/[a-zA-Z]+[:\/\/]+[A-Za-z0-9\-_]+\\.+[A-Za-z0-9\.\/%&=\?\-_]+/ie", "'<a href=\"\\0\" target=\"_blank\">'.urlreduce('\\0').'</a><div class=\"new_window\"> (Opens in new window) </div>\n'", $temp);[/code]The above code works fine, for an autolinking feature. But, I want it to ignore any URLs preceded by [code]image=[/code]I thought I could simply add a condition to the start of my match case, like so:[code]$temp = preg_replace("/[^image=][a-zA-Z]+[:\/\/]+[A-Za-z0-9\-_]+\\.+[A-Za-z0-9\.\/%&=\?\-_]+/ie", "'<a href=\"\\0\" target=\"_blank\">'.urlreduce('\\0').'</a><div class=\"new_window\"> (Opens in new window) </div>\n'", $temp);[/code]It doesn't work though - still matches on URLs preceded by image=.Cheers for your help,G. Quote Link to comment https://forums.phpfreaks.com/topic/5859-regular-expression-problem/ Share on other sites More sharing options...
toplay Posted March 26, 2006 Share Posted March 26, 2006 The [^image=] part won't work because it's not interpreted as "image=" but rather as each individual character (i, m, a, g, e, =).You need to use a negative lookbehind "(?<!)". Try this expression:'/(?<!image=)\\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|]/i' Quote Link to comment https://forums.phpfreaks.com/topic/5859-regular-expression-problem/#findComment-20890 Share on other sites More sharing options...
grum Posted March 26, 2006 Author Share Posted March 26, 2006 That did the trick, cheers.Do you mind if I ask more about it?'/(?<!image=)\\b(https?|ftp|file):\/\/[!--coloro:#FF0000--][span style=\"color:#FF0000\"][!--/coloro--][-A-Z0-9+&@#\/%?=~_|!:,.;][!--colorc--][/span][!--/colorc--]*[!--coloro:#33CC00--][span style=\"color:#33CC00\"][!--/coloro--][-A-Z0-9+&@#\/%=~_|] [!--colorc--][/span][!--/colorc--]/ie'In psuedo code, is that..any number of these characters [!--coloro:#FF0000--][span style=\"color:#FF0000\"][!--/coloro--][-A-Z0-9+&@#\/%?=~_|!:,.;] [!--colorc--][/span][!--/colorc--]followed by one of any of these characters [!--coloro:#33CC00--][span style=\"color:#33CC00\"][!--/coloro--][-A-Z0-9+&@#\/%=~_|][!--colorc--][/span][!--/colorc--]?If so, why?And I don't really get the word boundary thing. For my own curiosity, I tried your lookbehind statement and the word boundary at the start of my first code snippet. Why does it not work in that scenario?Thanks again!G. Quote Link to comment https://forums.phpfreaks.com/topic/5859-regular-expression-problem/#findComment-20906 Share on other sites More sharing options...
toplay Posted March 26, 2006 Share Posted March 26, 2006 I use RegexBuddy to help with formatting regex/PREG. It's well worth the $30 USD cost. See: [a href=\"http://www.regexbuddy.com\" target=\"_blank\"]http://www.regexbuddy.com[/a]Here's documentation on that regex for you to put in your code for future reference:[code]// (?<!image=)\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|!:,.;]*[-A-Z0-9+&@#/%=~_|]// // Assert that it is impossible to match the regex below with the match ending at this position (negative lookbehind) «(?<!image=)»// Match the characters "image=" literally «image=»// Assert position at a word boundary «\b»// Match the regular expression below and capture its match into backreference number 1 «(https?|ftp|file)»// Match either the regular expression below (attempting the next alternative only if this one fails) «https?»// Match the characters "http" literally «http»// Match the character "s" literally «s?»// Between zero and one times, as many times as possible, giving back as needed (greedy) «?»// Or match regular expression number 2 below (attempting the next alternative only if this one fails) «ftp»// Match the characters "ftp" literally «ftp»// Or match regular expression number 3 below (the entire group fails if this one fails to match) «file»// Match the characters "file" literally «file»// Match the characters "://" literally «://»// Match a single character present in the list below «[-A-Z0-9+&@#/%?=~_|!:,.;]*»// Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»// The character "-" «-»// A character in the range between "A" and "Z" «A-Z»// A character in the range between "0" and "9" «0-9»// One of the characters "+&@#/%?=~_|!:,.;" «+&@#/%?=~_|!:,.;»// Match a single character present in the list below «[-A-Z0-9+&@#/%=~_|]»// The character "-" «-»// A character in the range between "A" and "Z" «A-Z»// A character in the range between "0" and "9" «0-9»// One of the characters "+&@#/%=~_|" «+&@#/%=~_|»[/code] Quote Link to comment https://forums.phpfreaks.com/topic/5859-regular-expression-problem/#findComment-20919 Share on other sites More sharing options...
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