PHP convert empty array to string

use empty function to check if array is empty or not

return empty($xml_array)?"":$xml_array;

$parser = xml_parser_create('');
xml_parser_set_option($parser, XML_OPTION_TARGET_ENCODING, "UTF-8");
xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, 1);
xml_parse_into_struct($parser, trim($contents), $xml_values);
xml_parser_free($parser);
if (!$xml_values)
    return; //Hmm...
$xml_array = array ();
$parents = array ();
$opened_tags = array ();
$arr = array ();
$current = & $xml_array;
$repeated_tag_index = array (); 
foreach ($xml_values as $data)
{
    unset ($attributes, $value);
    extract($data);
    $result = array ();
    $attributes_data = array ();
    if (isset ($value))
    {
        if ($priority == 'tag')
            $result = $value;
        else
            $result['value'] = $value;
    }
    if (isset ($attributes) and $get_attributes)
    {
        foreach ($attributes as $attr => $val)
        {
            if($attr == 'xsi:type') continue;
            if($attr == 'xsi:nil') continue;

            if ($priority == 'tag')
                $attributes_data[$attr] = $val;
            else
                $result['attr'][$attr] = $val; //Set all the attributes in a array called 'attr'
        }
    }
    if ($type == "open")
    { 
        $parent[$level -1] = & $current;
        if (!is_array($current) or (!in_array($tag, array_keys($current))))
        {
            $current[$tag] = $result;
            if ($attributes_data)
                $current[$tag . '_attr'] = $attributes_data;
            $repeated_tag_index[$tag . '_' . $level] = 1;
            $current = & $current[$tag];
        }
        else
        {
            if (isset ($current[$tag][0]))
            {
                $current[$tag][$repeated_tag_index[$tag . '_' . $level]] = $result;
                $repeated_tag_index[$tag . '_' . $level]++;
            }
            else
            { 
                $current[$tag] = array (
                    $current[$tag],
                    $result
                ); 
                $repeated_tag_index[$tag . '_' . $level] = 2;
                if (isset ($current[$tag . '_attr']))
                {
                    $current[$tag]['0_attr'] = $current[$tag . '_attr'];
                    unset ($current[$tag . '_attr']);
                }
            }
            $last_item_index = $repeated_tag_index[$tag . '_' . $level] - 1;
            $current = & $current[$tag][$last_item_index];
        }
    }
    elseif ($type == "complete")
    {
        if (!isset ($current[$tag]))
        {
            $current[$tag] = $result;
            $repeated_tag_index[$tag . '_' . $level] = 1;
            if ($priority == 'tag' and $attributes_data)
                $current[$tag . '_attr'] = $attributes_data;
        }
        else
        {
            if (isset ($current[$tag][0]) and is_array($current[$tag]))
            {
                $current[$tag][$repeated_tag_index[$tag . '_' . $level]] = $result;
                if ($priority == 'tag' and $get_attributes and $attributes_data)
                {
                    $current[$tag][$repeated_tag_index[$tag . '_' . $level] . '_attr'] = $attributes_data;
                }
                $repeated_tag_index[$tag . '_' . $level]++;
            }
            else
            {
                $current[$tag] = array (
                    $current[$tag],
                    $result
                ); 
                $repeated_tag_index[$tag . '_' . $level] = 1;
                if ($priority == 'tag' and $get_attributes)
                {
                    if (isset ($current[$tag . '_attr']))
                    { 
                        $current[$tag]['0_attr'] = $current[$tag . '_attr'];
                        unset ($current[$tag . '_attr']);
                    }
                    if ($attributes_data)
                    {
                        $current[$tag][$repeated_tag_index[$tag . '_' . $level] . '_attr'] = $attributes_data;
                    }
                }
                $repeated_tag_index[$tag . '_' . $level]++; //0 and 1 index is already taken
            }
        }
    }
    elseif ($type == 'close')
    {
        $current = & $parent[$level -1];
    }
}

return ($xml_array);

} ?>

Just check your source array using empty: http://php.net/empty and return "" is empty() returned true. Add this at the begining of your function:

if( empty($myArray) ) {
   return "";
}

The empty array you see is the default value you set:

$result = array ();

You have the following alternatives:

1. Keep it as is - empty elements will have an empty array as value.
2. Set to "" (empty string) - empty elements will have an empty string as value.
3. Set to NULL - empty elements will be dropped if they have siblings with the same element name. Single empty elements will be preserved.

Depending on your need just take the default of your choice.

I first thought array_walk_recursive would be a great option, but it ignores empty arrays in the function call.

I would create a function, something like this. It goes through an array recursively and replaces array with string. (something like this)

function replaceArrayToString($arr = array()) {
    $newArr = array();
    foreach($arr as $key=>$value)
    {
        if (is_array($value))
        {
           unset($arr[$key]);

            //Is it an empty array, make it a string
            if (empty($value)) {
                $newArr[$key] = '';
            }
            else {
                $newArr[$key] = replaceArrayToString($value);
            }

        }
        else {
            $newArr[$key] = $value; 
        }

    }
    return $newArr;

}

and then call it from the end of your existing function xml2array() before returning the array.

    elseif ($type == 'close')
        {
        $current = & $parent[$level -1];
        }
    }

    $xml_array = replaceArrayToString($xml_array);
    return ($xml_array);
}