Regular Expression Pocket Reference, 2nd Edition

Examples

Example 1-13. Simple match

//Find Spider-Man, Spiderman, SPIDER-MAN, etc.
$dailybugle = "Spider-Man Menaces City!";

$regex = "/spider[- ]?man/i";

if (preg_match($regex, $dailybugle)) {
      //do something
}

Example 1-14. Match and capture group

//Match dates formatted like MM/DD/YYYY, MM-DD-YY,...
$date = "12/30/1969";
$p    = "!^(\\d\\d)[-/](\\d\\d)[-/](\\d\\d(?:\\d\\d)?)$!";

if (preg_match($p,$date,$matches) {
      $month = $matches[1];
      $day   = $matches[2];
      $year  = $matches[3];
}

Example 1-15. Simple substitution

//Convert <br> to <br /> for XHTML compliance
$text = "Hello world. <br>";

$pattern  = "{<br>}i";

echo preg_replace($pattern, "<br />", $text);

Example 1-16. Harder substitution

//urlify - turn URLs into HTML links
$text = "Check the web site, http://www.oreilly.com/catalog/regexppr.";
$regex =
        "{ \\b                      # start at word\n"
     .  "                           # boundary\n"
     .  "(                          # capture to $1\n"
     .  "(https?|telnet|gopher|file|wais|ftp) : \n"
     .  "                           # resource and colon\n"
     .  "[\\w/\\#~:.?+=&%@!\\-]+?   # one or more valid\n"
     .  "                           # characters\n"
     .  "                           # but take as little as\n"
     .  "                           # possible\n"
     .  ")\n"
     .  "(?=                        # lookahead\n"
     .  "[.:?\\-]*                  # for possible punct\n"
     .  "(?:[^\\w/\\#~:.?+=&%@!\\-] # invalid character\n"
     .  "|$)                        # or end of string\n"
     .  ") }x";


echo preg_replace($regex, "<a href=\"$1\">$1</a>", $text);