将List组件转换为list

Question

Is there an easy way to expand out a list to individual components? E.g. if a client requests the following lines: 1,5,6,10-15,20,21 is there an easy way using PHP (or MySQL directly) to convert this to a list of: 1,5,6,10,11,12,13,14,15,20,21.

I am thinking I can move each element into an array and then look for the '-' character in an 'a-b' component and use that to run a loop process to add numbers from 'a' through to 'b' but there may be an easier way.

Answer 1

Your process is correct and very understandable, and there seems to be no built-in function to do it. Using the range function makes it easier than with a regular for loop.

$values = explode (',', $str);

foreach ($values as $val) {
  if (strpos($val, '-') !== false) {
    $range_values = explode ('-', $val);
    foreach (range($range_values[0], $range_values[1]) as $val_to_add) {
      $values[] = $val_to_add;
    }
  }
}

sort($values);

$str = implode (',', $values);