php - Use mysql_fetch_array() with foreach() instead of while()

Solution:

There's not a good way to convert it to foreach, becausemysql_fetch_array() just fetches the next result from$result_select. If you really wanted to foreach, you could do pull all the results into an array first, doing something like the following:

$result_list = array();
while($row = mysql_fetch_array($result_select)) {
   result_list[] = $row;
}

foreach($result_list as $row) {
   ...
}
Copy code

But there's no good reason I can see to do that - and you still have to use the while loop, which is unavoidable due to howmysql_fetch_array() works. Why is it so important to use a foreach()?

EDIT: If this is just for learning purposes: you can't convert this to aforeach. You have to have a pre-existing array to use aforeach() instead of awhile(), andmysql_fetch_array() fetches one result per call - there's no pre-existing array forforeach() to iterate through.

Solution:

To useforeach would require you have an array that contains every row from the query result. Some DB libraries for PHP provide afetch_all function that provides an appropriate array but I could not find one formysql (however the mysqli extension does) . You could of course write your own, like so

function mysql_fetch_all($result) {
   $rows = array();
   while ($row = mysql_fetch_array($result)) {
     $rows[] = $row;
   }
   return $rows;
}
Copy code

However I must echo the "why?" Using this function you are creating two loops instead of one, and requring the entire result set be loaded in to memory. For sufficiently large result sets, this could become a serious performance drag. And for what?

foreach (mysql_fetch_all($result) as $row)
Copy code

vs

while ($row = mysql_fetch_array($result))
Copy code

while is just as concise and IMO more readable.

EDIT There is another option, but it is pretty absurd. You could use the Iterator Interface

class MysqlResult implements Iterator {
  private $rownum = 0;
  private $numrows = 0;
  private $result;

  public function __construct($result) {
    $this->result = $result;
    $this->numrows = mysql_num_rows($result);
  }

  public function rewind() {
    $this->rownum = 0;
  }

  public function current() {
    mysql_data_seek($this->result, $this->rownum);
    return mysql_fetch_array($this->result);
  }

  public function key() {
    return $this->rownum;
  }

  public function next() {
    $this->rownum++;
  }

  public function valid() {
    return $this->rownum < $this->numrows ? true : false;
  }
}

$rows = new MysqlResult(mysql_query($query_select));

foreach ($rows as $row) {
  //code...
}
Copy code

In this case, theMysqlResult instance fetches rows only on request just like withwhile, but wraps it in a nice foreach-able package. While you've saved yourself a loop, you've added the overhead of class instantiation and a boat load of function calls, not to mention a good deal of added code complexity.

But you asked if it could be done without usingwhile (orfor I imagine). Well it can be done, just like that. Whether it should be done is up to you.

Solution:

the most obvious way to makeforeach a possibility includes materializing the whole resultset in an array, which will probably kill you memory-wise, sooner or later. you'd need to turn to iterators to avoid that problem. see http://www.php.net/~helly/php/ext/spl/

Solution:

You could just do it like this

$query_select = "SELECT * FROM shouts ORDER BY id DESC LIMIT 8;"; 

$result_select = mysql_query($query_select) or die(mysql_error());

 foreach($result_select as $row){
    $ename = stripslashes($row['name']);
    $eemail = stripcslashes($row['email']);
    $epost = stripslashes($row['post']);
    $eid = $row['id'];

    $grav_url = "http://www.gravatar.com/avatar.php?gravatar_id=".md5(strtolower($eemail))."&size=70";

    echo ('<img src = "' . $grav_url . '" alt="Gravatar">'.'<br/>');

    echo $eid . '<br/>';

    echo $ename . '<br/>';

    echo $eemail . '<br/>';

    echo $epost . '<br/><br/><br/><br/>';
 }
Copy code