Question

I have a simple table with 2 colums: ID and Name. It looks like this:

License_ID      License_Name
   5             xxx
   8             yyy
   13            zzz

I want to write this table as an array, and I want to be able to find the license_id when license_name is provided. How can I write this array?

Edit: I can write the array the same as the answer nickb provided,

$array = array(
    'xxx' => 5,
    'yyy' => 8,
    'zzz' => 13
);

but I want to have the license_id and license_name as key instead of using value of license_name as key.

Answer 1

Form an array with keys corresponding to the license name and values corresponding to the license ID, like so:

$sql = 'SELECT * FROM table'; // Optionally add a WHERE clause
$result = mysql_query( $sql);
$array = array();
while( $row = mysql_fetch_array( $result))
{
    // Form the array
    $array[ $row['License_Name'] ] = $row['License_ID'];
}
mysql_free_result( $result);

To omit the table and use a global variable, use the same technique:

$array = array(
    'xxx' => 5,
    'yyy' => 8,
    'zzz' => 13
);

Now, to lookup the license ID, all you need is:

$license_id = 8;
$id = $array[ $license_id ]; // $id = 'yyy';

Edit: Here’s an alternative way to represent the way in a more clear manner:

$array = array(
    array(
        'license_id' => 5,
        'license_name' => 'xxx'
    ),
    array(
        'license_id' => 8,
        'license_name' => 'yyy'
    ),
    array(
        'license_id' => 13,
        'license_name' => 'zzz'
    )
);

Then, to find the license_id when license_name is provided, loop to find your result:

$license_name = 'zzz';
foreach( $array as $entry)
{
    if( $entry['license_name'] == $license_name)
    {
        echo 'Found ID of ' . $license_name . ' - ' . $entry['license_id'];
        break;
    }
}

OR, and even more direct way to prevent looping is to modify the above technique to have each sub-array contain the license_name as its key, like so:

$array = array(
    'xxx' => array(
        'license_id' => 5,
        'license_name' => 'xxx'
    ),
    'yyy' => array(
        'license_id' => 8,
        'license_name' => 'yyy'
    ),
    'zzz' => array(
        'license_id' => 13,
        'license_name' => 'zzz'
    )
);

Now, to find the license_id, you can do it directly once you know the license_name:

$license_name = 'zzz';
$license_id = $array[ $license_name ]['license_id'];