return multiple variables as array and extract them

Question

I have a function that get data from a table and there are multiple columns (variables). I need to return all the variables from the function to use them.

I've tried multiple ways but I can't make it work:

return array($var, $var2, $var3, $etc);

return compact($var, $var2, $var3, $etc);

Now I use extract() but I'm doing something wrong:

$data = $functions->my_function($id);

// I must check first if there are results
// will this work?
if (is_array($data)) {
    extract($data);
    // now I can use the variables from the function:
    echo $var, $var2, $var3, $etc;
}

Instead of declaring the variables one by one:

$var = $data[0];
$var2 = $data[1];

Maybe the problem are the variables names?

$stmt->bind_result($id, $use, $type, $status, $bhk, $baths, $area_1, $area_2, $city, $zone, $sale_price, $monthly_price, $description);

I read something about wrong variable names won't work with extract() in the php.net comments.

compact('var', 'var2', 'var3', 'etc);

splash58
– splash58

2016-01-01 17:26:02 +00:00
Commented Jan 1, 2016 at 17:26 — splash58
– splash58, Commented Jan 1, 2016 at 17:26
Thanks that's working!

Chazy Chaz
– Chazy Chaz

2016-01-01 17:32:09 +00:00
Commented Jan 1, 2016 at 17:32 — Chazy Chaz
– Chazy Chaz, Commented Jan 1, 2016 at 17:32

random_user_name · Accepted Answer · 2016-01-01 17:40:16Z

The reason your extract is not working is because you need to return an associative array. You can do this manually, or you can use compact properly by passing variable names, not variable values:

function my_function() {
    $var = 'Happy';
    $var2 = 'New';
    $var3 = 'Year';
    return array(
        'var'  => $var,
        'var2' => $var2,
        'var3' => $var3
        // ... etc ...
    );
    // Alternate method, with compact
    return compact('var', 'var2', 'var3');
}

$values = my_function();
extract($values);
echo $var; // outputs 'Happy'
echo $var2; // outputs 'New'
echo $var3; // outputs 'Year'

Edit
Extract is not best-practice. When reading the code, it's a mystery where the variables suddenly appear from, and makes it more difficult to maintain.

Better would be to check / get the values explicitly from the array:

$values = my_function();
$var  = $values['var'];
$var2 = $values['var2'];
$var3 = $values['var3'];
echo $var; // outputs 'Happy'
echo $var1; // outputs 'New'
echo $var3; // outputs 'Year'

Depending on the structure of your code, you have to decide if you can rely on that function to always return those values, or if you need to check them. If you need to check multiple keys / values, then I typically like to write a utility function for that sort of thing:

function get_val( $key, $array, $default = FALSE) {
    $array = (array)$array;
    return ( isset( $array[ $key ] ) ) ? $array[ $key ] : $default;
}

Then, you'd use it like so:

$values = my_function();
$var  = get_val( 'var', $values );
$var2 = get_val( 'var2', $values );
$var3 = get_val( 'var3', $values );
echo $var; // outputs 'Happy'
echo $var1; // outputs 'New'
echo $var3; // outputs 'Year'

Lastly, your function that returns the row from the DB should probably be responsible for doing the validation / returning something meaningful. For example, if no rows, then return FALSE, then you can check like so:

function my_function( $id ) {
     // your code to get the row based on the id

     // then, check that a row was returned...
     if ( ! count( $row ) ) {
          return FALSE;
     } else {
          // return the row
     }
}

$values = my_function();
if ( $values !== FALSE ) {
    // do stuff, because we know we have a valid row
}

Thanks! And how would I do the check? Inside the function using num_rows or is there another easy way?

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