How to convert the string - One.Two.Three into array keys?

Question

PHP

Tell me how to convert the string in php:
one.two.three
into
array[one][two][three] = [];
taking into account the fact that there may be Four, or there may be no Three.
Those. I need words separated by a dot to be array keys
. I did this, but it's not correct:

private function _parse_var($string, $vars = []) {
    if ( strpos($string, '.') === false ) {
      if ( array_key_exists($string, $vars) ) return $vars[$string];
    } else {
      $string = explode('.', $string);
      $string = array_filter($string);
      
      if ( count($string) == 2 ) {
        if ( isset($vars[$string[0]][$string[1]]) ) return $vars[$string[0]][$string[1]];
      } elseif ( count($string) == 3 ) {
        if ( isset($vars[$string[0]][$string[1]][$string[2]]) ) return $vars[$string[0]][$string[1]][$string[2]];
      }
    }
    return false;
  }

Answer 1

Array dot notation:
https://medium.com/@assertchris/dot-notation-3fd3e...

Answer 2

my version

function &ap(&$input, $path = null, $set_value = null)
{
    if ( !is_null($path) )
    {
        if ( !is_array($path) )
        {
            $path = p2a($path);
        }

        $node = &$input;

        if ( !is_null($set_value) )
        {
            foreach ( $path as $segment )
            {
                if ( !isset($node[$segment]) || !is_array($node[$segment]) )
                {
                    $node[$segment] = false;
                }

                $node = &$node[$segment];
            }

            $node = $set_value;

            return $node;
        }
        else
        {
            foreach ( $path as $segment )
            {
                isset($node[$segment]) || $node[$segment] = null;

                $node = &$node[$segment];
            }

            return $node;
        }
    }
    else
    {
        return $input;
    }
}

function p2a($path, $separator = false)
{
    if ( $path === false || $path === '' )
    {
        return array();
    }
    else
    {
        if ( $separator )
            $separator = '/' . $separator . '/';
        else
            $separator = '/';

        return explode($separator, $path);
    }
}

usage:
get node value
will return $array['path']['to']['node'] or null if doesn't exist
create/replace node value
will do $array['path']['to']['node' ] = 'klmn'
get link to node

$link = &ap($array, 'path/to/node');

$link = 123;

$array['path']['to']['node'] becomes = 123
there is one small bug in the form of creating nodes with a value equal to an empty array that were accessed, but did not exist
and cannot be accessed (when writing) to node, the path to which lies through the given scalar value, that is, if path/to/node = 123, then it is impossible to create a path/to/node/some node. well, here is the logic of the universe, here my powers, as it were, all the
numerical segments can be used too