finding common prefix of array of strings

Question

I have an array like this:

$sports = array(
\'Softball - Counties\',
\'Softball - Eastern\',
\'Softball - North Harbour\',
\'Softball - South\',
\'Softball -         


        

Answer 1

This is an addition to the @Gumbo answer. If you want to ensure that the chosen, common prefix does not break words, use this. I am just having it look for a blank space at the end of the chosen string. If that exists we know that there was more to all of the phrases, so we truncate it.

function product_name_intersection($array){

    $pl = 0; // common prefix length
    $n = count($array);
    $l = strlen($array[0]);
    $first = current($array);

    while ($pl < $l) {
        $c = $array[0][$pl];
        for ($i=1; $i<$n; $i++) {
            if (!isset($array[$i][$pl]) || $array[$i][$pl] !== $c) break 2;
        }
        $pl++;
    }
    $prefix = substr($array[0], 0, $pl);

    if ($pl < strlen($first) && substr($prefix, -1, 1) != ' ') {

        $prefix = preg_replace('/\W\w+\s*(\W*)$/', '$1', $prefix);
    }

    $prefix =  preg_replace('/^\W*(.+?)\W*$/', '$1', $prefix);

    return $prefix;
}