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问题:

I have never really thought about this until today, but after searching the web I didn't really find anything. Maybe I wasn't wording it right in the search.

Given an array (of multiple dimensions or not):

$data = array('this' => array('is' => 'the'), 'challenge' => array('for' => array('you')));

When var_dumped:

array(2) { ["this"]=> array(1) { ["is"]=> string(3) "the" } ["challenge"]=> array(1) { ["for"]=> array(1) { [0]=> string(3) "you" } } }

The challenge is this: What is the best optimized method for recompiling the array to a useable array for PHP? Like an undump_var() function. Whether the data is all on one line as output in a browser or whether it contains the line breaks as output to terminal.

Is it just a matter of regex? Or is there some other way? I am looking for creativity.

UPDATE: Note. I am familiar with serialize and unserialize folks. I am not looking for alternative solutions. This is a code challenge to see if it can be done in an optimized and creative way. So serialize and var_export are not solutions here. Nor are they the best answers.

回答1:

var_export or serialize is what you're looking for. var_export will render a PHP parsable array syntax, and serialize will render a non-human readable but reversible "array to string" conversion...

Edit Alright, for the challenge:

Basically, I convert the output into a serialized string (and then unserialize it). I don't claim this to be perfect, but it appears to work on some pretty complex structures that I've tried...

function unvar_dump($str) {     if (strpos($str, "\n") === false) {         //Add new lines:         $regex = array(             '#(\\[.*?\\]=>)#',             '#(string\\(|int\\(|float\\(|array\\(|NULL|object\\(|})#',         );         $str = preg_replace($regex, "\n\\1", $str);         $str = trim($str);     }     $regex = array(         '#^\\040*NULL\\040*$#m',         '#^\\s*array\\((.*?)\\)\\s*{\\s*$#m',         '#^\\s*string\\((.*?)\\)\\s*(.*?)$#m',         '#^\\s*int\\((.*?)\\)\\s*$#m',         '#^\\s*bool\\(true\\)\\s*$#m',         '#^\\s*bool\\(false\\)\\s*$#m',         '#^\\s*float\\((.*?)\\)\\s*$#m',         '#^\\s*\[(\\d+)\\]\\s*=>\\s*$#m',         '#\\s*?\\r?\\n\\s*#m',     );     $replace = array(         'N',         'a:\\1:{',         's:\\1:\\2',         'i:\\1',         'b:1',         'b:0',         'd:\\1',         'i:\\1',         ';'     );     $serialized = preg_replace($regex, $replace, $str);     $func = create_function(         '$match',          'return "s:".strlen($match[1]).":\\"".$match[1]."\\"";'     );     $serialized = preg_replace_callback(         '#\\s*\\["(.*?)"\\]\\s*=>#',          $func,         $serialized     );     $func = create_function(         '$match',          'return "O:".strlen($match[1]).":\\"".$match[1]."\\":".$match[2].":{";'     );     $serialized = preg_replace_callback(         '#object\\((.*?)\\).*?\\((\\d+)\\)\\s*{\\s*;#',          $func,          $serialized     );     $serialized = preg_replace(         array('#};#', '#{;#'),          array('}', '{'),          $serialized     );      return unserialize($serialized); }

I tested it on a complex structure such as:

array(4) {   ["foo"]=>   string(8) "Foo"bar""   [0]=>   int(4)   [5]=>   float(43.2)   ["af"]=>   array(3) {     [0]=>     string(3) "123"     [1]=>     object(stdClass)#2 (2) {       ["bar"]=>       string(4) "bart"       ["foo"]=>       array(1) {         [0]=>         string(2) "re"       }     }     [2]=>     NULL   } }

回答2:

There's no other way than manual parsing depending on the type. I didn't add support for objects, but it's very similar to the arrays one; you just need to do some reflection magic to populate not only public properties and to not trigger the constructor.

EDIT: Added support for objects... Reflection magic...

function unserializeDump($str, &$i = 0) {     $strtok = substr($str, $i);     switch ($type = strtok($strtok, "(")) { // get type, before first parenthesis          case "bool":              return strtok(")") === "true"?(bool) $i += 10:!$i += 11;          case "int":              $int = (int)substr($str, $i + 4);              $i += strlen($int) + 5;              return $int;          case "string":              $i += 11 + ($len = (int)substr($str, $i + 7)) + strlen($len);              return substr($str, $i - $len - 1, $len);          case "float":              return (float)($float = strtok(")")) + !$i += strlen($float) + 7;          case "NULL":              return NULL;          case "array":              $array = array();              $len = (int)substr($str, $i + 6);              $i = strpos($str, "\n", $i) - 1;              for ($entries = 0; $entries \n  ", $i));                  } else {                      $key = (int)substr($str, $i + 1);                      $i += strlen($key);                  }                  $i += $indent + 5; // jump line                  $array[$key] = unserializeDump($str, $i);              }              $i = strpos($str, "}", $i) + 1;              return $array;          case "object":              $reflection = new ReflectionClass(strtok(")"));              $object = $reflection->newInstanceWithoutConstructor();              $len = !strtok("(") + strtok(")");              $i = strpos($str, "\n", $i) - 1;              for ($entries = 0; $entries \n  ", $i)?:INF, strpos($str, "\":protected]=>\n  ", $i)?:INF, $priv = strpos($str, "\":\"", $i)?:INF));                  if ($priv == $i) {                      $ref = new ReflectionClass(substr($str, $i + 3, - 3 - $i + $i = strpos($str, "\":private]=>\n  ", $i)));                      $i += $indent + 13; // jump line                  } else {                      $i += $indent + ($str[$i+1] == ":"?15:5); // jump line                      $ref = $reflection;                  }                  $prop = $ref->getProperty($key);                  $prop->setAccessible(true);                  $prop->setValue($object, unserializeDump($str, $i));              }              $i = strpos($str, "}", $i) + 1;              return $object;      }     throw new Exception("Type not recognized...: $type"); }

(Here are a lot of "magic" numbers when incrementing string position counter $i, mostly just string lengths of the keywords and some parenthesis etc.)

回答3:

If you want to encode/decode an array like this, you should either use var_export(), which generates output in PHP's array for, for instance:

array(   1 => 'foo',   2 => 'bar' )

could be the result of it. You would have to use eval() to get the array back, though, and that is a potentially dangerous way (especially since eval() really executes PHP code, so a simple code injection could make hackers able to gain control over your PHP script).

Some even better solutions are serialize(), which creates a serialized version of any array or object; and json_encode(), which encodes any array or object with the JSON format (which is more preferred for data exchange between different languages).

回答4:

The trick is to match by chunks of code and "strings", and on strings do nothing but otherwise do the replacements:

$out = preg_replace_callback('/"[^"]*"|[^"]+/','repl',$in);  function repl($m) {     return $m[0][0]=='"'?         str_replace('"',"'",$m[0])     :         str_replace("(,","(",             preg_replace("/(int\((\d+)\)|\s*|(string|)\(\d+\))/","\\2",                 strtr($m[0],"{}[]","(), ")             )         ); }

outputs:

array('this'=>array('is'=>'the'),'challenge'=>array('for'=>array(0=>'you')))

(removing ascending numeric keys starting at 0 takes a little extra accounting, which can be done in the repl function.)

ps. this doesn't solve the problem of strings containing ", but as it seems that var_dump doesn't escape string contents, there is no way to solve that reliably. (you could match \["[^"]*"\] but a string may contain "] as well)

回答5:

Use regexp to change array(.) { (.*) } to array($1) and eval the code, this is not so easy as written because You have to deal with matching brackets etc., just a clue on how to find solution ;)