note 75170 deleted from function.preg-replace by colder

Note Submitter: markschmid at NOSPAM dot gmx dot ch ---- Hi Admins, Someone mailed me a thank you for my code snippet here in preg_replace() and that he might donate something to the PHP project. So I thought I'd rewrite my entry, making it even better by removing some typos and the unneeded CSS classes which I formerly forgot to remove. Please replace my entire entry from 16-Apr-2007 11:38 with the following one, thanx: ---------------------- Reformatting text I thought I'd share this: It took me half a day to find the solution to this little problem, regular expressions being somewhat hard to grasp if one is not used to them: I had the situation where I wanted to reformat text entered into a forum or email with too many unneeded newline or line break characters. You know, someone enters a text, thinking he has to break the lines himself while you'd rather have no new line characters and wrap the text with a PHP function or an HTML table. So I had texts with too many newline characters ("\n") which had to be removed BEFORE the text could be (re-)wrapped automatically. However, paragraphs separated by two or more newline characters ("\n\n") should remain separated paragraphs! After much testing I came up with this solution: <?php // $originalString = Your original, badly formatted string // with too many unneeded line breaks as // it might come from a user entry. $originalString = "Humpty Dumpty \r\n"; $originalString .= "sat on a wall \r\n"; $originalString .= "minding \r\n"; $originalString .= "his own business. \r\n"; $originalString .= "\r\n"; $originalString .= "After two hours\r\n"; $originalString .= "Puff the magic \r\n"; $originalString .= "dragon came along. \r\n\r\n"; // *** Regular Expression Syntax used: // "\ " = escaped space character // "\n" = newline character (=line break from Linux) // "\r\n" = carriage return and newline character // (=line break from Windows) // "\s" = any whitespace character // "\S" = any character that is not a whitespace character // "+" = One or more of this character // (?=...) = Positive Lookahead assertion (sort of like ==) // (ahead = AFTER current position). // (?<=...) = Positive Lookbehind assertion (sort of like ==) // (behind = BEFORE current position). // With the first search pattern we select single newline // characters preceded and followed by any non-whitespace // character: $searchPatterns[0] = "/(?<=\S)\n(?=\S)/"; // With the second search pattern we select single newline // characters preceded by a non-whitespace character, then // followed by one or more spaces as users might enter them // and then followed by any non-whitespace character: $searchPatterns[1] = "/(?<=\S)\ +\n(?=\S)/"; // Do the same for Windows style line breaks for texts // entered from Windows computers: $searchPatterns[2] = "/(?<=\S)\r\n(?=\S)/"; $searchPatterns[3] = "/(?<=\S)\ +\r\n(?=\S)/"; // Note: We don't have to use ksort($searchPatterns), as // suggested in PHP documentation, because the order in // which $searchPatterns are found is not relevant for us. // Replace all the found $searchPatterns with $replacement, // a single space: $replacement = " "; // Now let preg_replace() do the searching and replacing: $reformattedString = preg_replace($searchPatterns, $replacement, $originalString); // Show results: echo 'Original Text:<br>'; // Show original string for HTML: echo nl2br($originalString); echo '<br><br>'; echo 'And here is the reformatted text:<br>'; // Show reformatted string for HTML: echo nl2br($reformattedString); echo '<br><br>'; // PS: Now you can easily re-wrap the text in $reformattedString // with a PHP function of HTML tables. ?> Greetings, Markie