PHP只解析数组中的第一个元素

Question

I'm working on a periodic table, in which I retrieve all the elements from my database. I want to place the elements in their respective position in the periodic table.

E.g.: Hydrogen is in row 1, cell 1 - Helium is in row 1, cell 18. The cells between those two should therefore be blank.

The problem is, that when I run my for-loop and compare the position - which is stored in my database - and the ID I've given each cell (which is the same as the position-outcome from the database), it only parses the first element and then stops.

It returns the first one 1-1 (Helium - Row 1, cell 1) and parses it like it should. Then the next one, which would be 1-2 (Row 1, cell 2), and from here on it just stops.

This is my query

// SQL Query for retrieving elements
$query = "
    SELECT 
        id, name, symbol, row, cell
    FROM 
        elements
    ORDER BY
        id
";
$objResult = $objConnection->query($query);

while ($row = $objResult->fetch_assoc()) {
    // Creating two-dimensional, associative array containing each element
    $ele[] = array(
        'id' => $row['id'],
        'name' => $row['name'],
        'symbol' => $row['symbol'],
        'position' => $row['row'].'-'.$row['cell']
    );
}

And my for-loops

// Element counter
$cnt = 0;

// Creating tr's and td's
for($i = 1; $i <= 9; $i++) {
    echo '<tr>';
        for($h = 1; $h <= 18; $h++) {
            $cell = $i.'-'.$h;
            $pos = $ele[$cnt]['position'];

            echo '<td id="'.$cell.'">';
            if($pos == $cell) {
                echo $ele[$cnt]['symbol'];
            }
            echo '</td>';
            $cnt++;
        }
echo '</tr>';

I hope you can help me, cus I'm pretty stuck.

Answer 1

You should rethink your array and make it associative. Why don't you make the key of your array the field. like this:

$ele[ $row['row'].'-'.$row['cell'] ] = array(
    'id' => $row['id'],
    'name' => $row['name'],
    'symbol' => $row['symbol']
);

and then in your loop you can easily find the required element:

for($i = 1; $i <= 9; $i++) {
echo '<tr>';
    for($h = 1; $h <= 18; $h++) {
        $cell = $i.'-'.$h;

        echo '<td id="'.$cell.'">';
        if(isset($ele[$cell]) {
            echo $ele[$cell]['symbol'];
        }
        echo '</td>';
        $cnt++;
    }
echo '</tr>';