public static function removeIndex(string $list, $index, string $separator): string
    {
        $items = self::explode($separator, $list);
        if (isset($items[$index])) {
            unset($items[$index]);
        }
        return implode($separator, $items);
    }
public static function removeIndex(string $list, $index, string $separator): string
    {
        $items = self::explode($separator, $list);
        if (isset($items[$index])) {
            unset($items[$index]);
        }
        return implode($separator, $items);
    }
public static function removeIndex ( string $ list , $ index , string $ separator ) : string { $ items = self :: explode ( $ separator , $ list ) ; if ( isset ( $ items [ $ index ] ) ) { unset ( $ items [ $ index ] ) ; } return implode ( $ separator , $ items ) ; }
Remove index.

@param string $list
@param string|int $index
@param string $separator
@return string
Remove index .