CODEWITHSUNDEEP
phploops
Craig Shipman
Craig Shipman

Reputation: 187

Two Dimensional arrays and both indexes

I have data coming from a query and loading it into a 2 dimensional array inside a loop.

I have the below code but when it prints out the array the index is missing.

How do I load a 2 dimensional aray with the first index being the $id value and second index being the $UserEmail and then how would I loop through the array to pull out each index ($id, $UserEmail)?

//the query
$query = "select id, UserEmail from User";
$result = mysql_query($query);
while($row = mysql_fetch_array($result))
{
    $ue = $row['UserEmail'];
    $id = $row['id'];
    if (strpos($ue,','))
    {
        $UserArrayEmail = explode(',',$ue);
        foreach ($UserEmailArray as $u)
        {
            $ArrayTerm[$id][] = $u;
        }
    }
}

//looping through the array and getting value from $id and $UserEmail
foreach( $ArrayTerm as $ArrayT ) {
    print_r($ArrayT);
    foreach( $ArrayT as $value ) {
        echo $value . "<br/>";
    }
}

Please help.

Upvotes: 1

Views: 103

Answers (1)

Craig Taub
Craig Taub

Reputation: 4179

mysql_connect() is deprecated your solution should use PDO instead.

This is how it could be done with PDO and will fix the indexes:

//fetch array from query 
try { 
    $dbh = new PDO("mysql:host=$host; dbname=$dbname", $user, $pass); 
} catch (PDOException $e) { 
    // db error handling 
} 
$sth = $dbh->prepare("select id, UserEmail from user"); 
$sth->setFetchMode(PDO::FETCH_ASSOC); 
$sth->execute(); 
while($row = $sth->fetch())) { 
    $emails = $row['UserEmail']; 
    $id = $row['id']; 
    if (strpos($emails,',')) { 
         $UserEmailArray = explode(',',$emails); 
         foreach ($UserEmailArray as $email) { 
             $ArrayT[$id][] = $email; 
         } 
    } 
} 

//repeat the same but with PDO data with other loops 

}

Additionally, storing a list of data (in your case emails) in a single db column is not great for db normalization.

You have no type safety (VARCHAR can containanything), no referential integrity, no way of actually processing the data with the db (in SELECTs, JOINs etc). For the db, the list of email addresses is just a bunch of random characters.

The relational database model has a simple rule: one attribute, one value. So if you have multiple values, you have multiple rows. That's what you should fix first. You'll need another table named "user_email_addresses" or something.

With this new table it could be something like:

function html_escape($raw) { 
    return htmlentities($raw, ENT_COMPAT , 'utf-8'); 
} 

function log_exceptions($exception) { 
    echo $exception->getMessage(), '<br />', $exception->getTraceAsString();               
} 
set_exception_handler('log_exceptions'); 


$database = new PDO( 'mysql:host=localhost;dbname=DB', 'USER', 'PASS', array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION) ); 

$user_emails = array(); 
$emails = $database->query(' 
    SELECT user_id , email 
    FROM user_email_addresses'); 

foreach ($emails as $email) 
    $user_emails[ $email['user_id'] ][] = $email['email_address']; 

//address list
foreach ($user_emails as $user_id => $email_addresses) { 
    echo 'User: ' . html_escape($user_id) . '<br />'; 
    foreach ($email_addresses as $email_address) 
        echo html_escape($email_address) . '<br />'; 
    echo '<br />';

Upvotes: 2

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