php using while twice [duplicate]

Question

I'm currently new to php and learning but after doing a bit of test, I know that while can't be used twice but I'm not sure how to exactly reset it.
I see that in some scenarios people use reset($variable) but that doesn't seem to work in my case.
In case if it matters, I'm trying to use mysqli to retrieve back my dropdown menu as a selection, the first one works, but the second one doesn't works at all.

    <?php 
                    echo '<select>';
                    while(list($stateID, $stateName) = $result->fetch_row())
                    {   
                echo '<option value="$stateName">';
                echo "$stateName";
                echo '</option>';
                    } 
                    echo '</select>';
                    ?>
                <br>
                <br>
                To: &nbsp; &nbsp;
            <?php 
                 echo '<select>';
                    while(list($stateID, $stateName) = $result2->fetch_row())
                    {   
                echo '<option value="$stateName">';
                echo "$stateName";
                echo '</option>';
                    }
            echo '</select>';
                    ?>

additionally, in case if it's needed, here's my results on searching in mysql.

    <?php
include 'connect.php';
$query = "SELECT * FROM LOCATION";
$result = $mysqli->query($query, MYSQLI_STORE_RESULT);
$result2 = $mysqli->query($query, MYSQLI_STORE_RESULT);
if(!$result) {
    echo($mysqli->error);
    exit();
}
?>

While this method works where I created 2 variables with results 1 and 2, but I have a feeling this isn't the right way to go, especially in the event if I need to reuse the same code over and over again.

Kryten · Accepted Answer · 2016-10-15 15:25:42Z

What you're doing in those while statements is stepping over the list of rows you got from the database. It's true that you can't iterate over the list twice^*, so you can try something different: iterate over the list once, and save the results so you can reuse it. For example:

Do this after you query the database:

$data = [];
while(list($stateID, $stateName) = $result->fetch_row())
{   
    $data[] = [ 'stateID' => $stateID, 'stateName' => $stateName ];
}

All I've done here is iterated over the list of rows and saved the data into a variable. Now you can use the variable instead of trying to access the MySQL results:

echo '<select>';
foreach ($data as $d) {
    echo '<option value="'.$d['stateName'].'">";
    echo $d['stateName'];
    echo '</option>';
}

And because the data is stored in an array you can use it as many times as you like.

^* It may be possible to reset the pointer on the MySQL result set, but my approach is simpler and (probably) performs a little better, since you've copied the data you want into a plain old PHP array

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