php - Access a multidimensional array with dot notation

Question

I am looking to write a class which will be able to access multidimensional arrays with dot notation:

$config->get('bar.baz.foo');

Instead of:

$config['bar']['baz']['foo']

This is the class:

<?php

class DotNotation
{
    /**
     * @var array
     */
    protected $values = array();

    public function __construct(array $values)
    {
        $this->values = $values;
    }

    /**
     * @param string $path
     * @param string $default
     * @return mixed
     */
    public function get($path, $default = null)
    {
        $array = $this->values;

        if (!empty($path)) {
            $keys = explode('.', $path);
            foreach ($keys as $key) {
                if (isset($array[$key])) {
                    $array = $array[$key];
                } else {
                    return $default;
                }
            }
        }

        return $array;
    }

    /**
     * @param string $path
     * @param mixed $value
     */
    public function set($path, $value)
    {
        $link = & $this->values;

        if (!empty($path)) {
            $keys = explode('.', $path);
            foreach ($keys as $key) {

                if (!isset($link[$key])) {
                    $link[$key] = array();
                }

                if (!is_array($link[$key])) {
                    throw new RuntimeException("Can not set value for `$key` in `$path` path because it is not array.");
                }

                $link = & $link[$key];
            }
        }

        $link = $value;
    }

    /**
     * @param $path
     * @param array $values
     */
    public function add($path, array $values)
    {
        $get = (array)$this->get($path);
        $this->set($path, $this->arrayMergeRecursiveDistinct($get, $values));
    }

    /**
     * @param mixed $parameters
     */
    public function merge($parameters)
    {
        $this->add(null, (array)$parameters);
    }

    /**
     * @param string $path
     * @return bool
     */
    public function have($path)
    {
        $keys = explode('.', $path);
        $array = $this->values;
        foreach ($keys as $key) {
            if (isset($array[$key])) {
                $array = $array[$key];
            } else {
                return false;
            }
        }

        return true;
    }

    /**
     * array_merge_recursive does indeed merge arrays, but it converts values with duplicate
     * keys to arrays rather than overwriting the value in the first array with the duplicate
     * value in the second array, as array_merge does. I.e., with array_merge_recursive,
     * this happens (documented behavior):
     *
     * array_merge_recursive(array('key' => 'org value'), array('key' => 'new value'));
     *     => array('key' => array('org value', 'new value'));
     *
     * arrayMergeRecursiveDistinct does not change the datatypes of the values in the arrays.
     * Matching keys' values in the second array overwrite those in the first array, as is the
     * case with array_merge, i.e.:
     *
     * arrayMergeRecursiveDistinct(array('key' => 'org value'), array('key' => 'new value'));
     *     => array('key' => array('new value'));
     *
     * Parameters are passed by reference, though only for performance reasons. They're not
     * altered by this function.
     *
     * If key is integer, it will be merged like array_merge do:
     * arrayMergeRecursiveDistinct(array(0 => 'org value'), array(0 => 'new value'));
     *     => array(0 => 'org value', 1 => 'new value');
     *
     * @param array $array1
     * @param array $array2
     * @return array
     * @author Daniel <daniel (at) danielsmedegaardbuus (dot) dk>
     * @author Gabriel Sobrinho <gabriel (dot) sobrinho (at) gmail (dot) com>
     * @author Anton Medvedev <anton (at) elfet (dot) ru>
     */
    protected function arrayMergeRecursiveDistinct(array &$array1, array &$array2)
    {
        $merged = $array1;

        foreach ($array2 as $key => &$value) {
            if (is_array($value) && isset ($merged[$key]) && is_array($merged[$key])) {
                if (is_int($key)) {
                    $merged[] = $this->arrayMergeRecursiveDistinct($merged[$key], $value);
                } else {
                    $merged[$key] = $this->arrayMergeRecursiveDistinct($merged[$key], $value);
                }
            } else {
                if (is_int($key)) {
                    $merged[] = $value;
                } else {
                    $merged[$key] = $value;
                }
            }
        }

        return $merged;
    }
}

How can I improve this class to not use explode?

Answer 1

You can write it using strtok() instead of explode():

$a = array('foo' => array('bar' => array('baz' => 1)));

function resolve(array $a, $path, $default = null)
{
  $current = $a;
  $p = strtok($path, '.');

  while ($p !== false) {
    if (!isset($current[$p])) {
      return $default;
    }
    $current = $current[$p];
    $p = strtok('.');
  }

  return $current;
}

var_dump(resolve($a, 'foo.bar'));

// array('baz' => 1)