Separate string using array

This uses regex to do it.

• Get an escaped version of town names for regex. Make sure none of your names town names have a / in them, or we can't use array_map() (preg_quote()'s 2nd argument is the delimiter).
• Join them with the pipe |.
• String build and run the regex.
• The $matches will have name as 1 and and town as 2 indexes.

PHP

$string = 'John Smith Smithville';
$townlist = array('smithville', 'janeville', 'placeville');

if (preg_match_all(
      '/^(.*)\s(' . implode('|', array_map('preg_quote', $townlist)) . ')$/i',
      $string,
      $matches
))
{
    var_dump($matches);
}

It works!

Output

array(3) {
  [0]=>
  array(1) {
    [0]=>
    string(21) "John Smith Smithville"
  }
  [1]=>
  array(1) {
    [0]=>
    string(10) "John Smith"
  }
  [2]=>
  array(1) {
    [0]=>
    string(10) "Smithville"
  }
}

This does the trick I think

• For each item in the list, get the position in the original string
• If we get a position, we know it is in the string
• Create an array of the first part and the second part
• Break from the loop, since we found what we needed
• Return the value
• Returns an empty array if we don't find anything

Should work, did a few tests.

$string = "John Smith Smithville";
$townlist = array("smithville", "janeville", "placeville");

function stringSeperation($string, $list)
{
    $result = array();

    foreach($list as $item)
    {
        $pos = strrpos(strtolower($string), strtolower($item));
        if($pos !== false)
        {
            $result = array(trim(substr($string, 0, $pos)), trim(substr($string, $pos)));
            break;
        }
    }

    return $result;
}

var_dump(stringSeperation($string, $townlist));

Have you think about "special cases", such as: "John Smith New York"? or "New York New York" (the name can contains space, and person name can be the same with the city)

I think that the more approriate solution is: for every string str, we check with all the city name. The check procedure is (pseudo code):

foreach str in strArray[]
  foreach city in cities

     tmp = Get the substring in the end of str, which equal the length of the "city"
     if (tmp == city) then {name = substring(str, 0, strlen(str) - strlen(tmp)); break;}