Array to string conversion error when sorting array

Hello! Suppose I have a database with a column called "weight" and I have this function in my model:

Code:

public function test()
    {
        return $this->select('weight')
                    ->distinct()
                    ->findAll();
    }

 
Then I call this function in my controller:

Code:

$model = new MyModel();
$test = $model->test();

Then I put the $test variable inside $data and pass it to my view file. Now in the view file I print the array:

Code:

<?php print_r($test); ?>

Here is the result I get:

Array ( [0] => Array ( [weight] => 90 kg ) [1] => Array ( [weight] => 92 kg ) [2] => Array ( [weight] => 100 kg ) [3] => Array ( [weight] => 94 kg ) [4] => Array ( [weight] => 98 kg ) [5] => Array ( [weight] => 125 kg ) )

If I try to sort $test using asort($test), it works. But if I use natsort($test), I get error "Array to string conversion." The same happens if I use array_multisort($test, SORT_NATURAL) or sort($test, SORT_NATURAL). I have no idea why it happens. Could you please help me?

You're trying to sort the values of $test as if they are alphanumeric strings (this is what "natural ordering" is) but the aren't strings, they're Arrays. Take another look at it:

PHP Code:

$test = [
  0 => ['weight' => '90 kg'],
  1 => ['weight' => '92 kg'],
  2 => ['weight' => '100 kg'],
  3 => ['weight' => '94 kg'],
  4 => ['weight' => '98 kg'],
  5 => ['weight' => '125 kg']
]; 


Anything that attempts to sort this by natural order is going to fail because you can't convert an Array to a string. This is why your the last three commands fail. 

I also suspect that asort isn't actually working as you intended either. 

PHP Code:

php > $test = [
php >  0 => ['weight' => '90 kg'],
php >  1 => ['weight' => '92 kg'],
php >  2 => ['weight' => '100 kg'],
php >  3 => ['weight' => '94 kg'],
php >  4 => ['weight' => '98 kg'],
php >  5 => ['weight' => '125 kg']
php > ];
php > var_dump(asort($test));
php shell code:1:
bool(true)
php > var_dump($test);
php shell code:1:
array(6) {
  [2] =>
  array(1) {
    'weight' =>
    string(6) "100 kg"
  }
  [5] =>
  array(1) {
    'weight' =>
    string(6) "125 kg"
  }
  [0] =>
  array(1) {
    'weight' =>
    string(5) "90 kg"
  }
  [1] =>
  array(1) {
    'weight' =>
    string(5) "92 kg"
  }
  [3] =>
  array(1) {
    'weight' =>
    string(5) "94 kg"
  }
  [4] =>
  array(1) {
    'weight' =>
    string(5) "98 kg"
  }
}
php > 


Here's a hint that might get you started in the right direction:

PHP Code:

php > foreach ($test as $k=>&$v){$v = $v['weight'];}
php > unset($v); var_dump($test);
php shell code:1:
array(6) {
  [0] =>
  string(5) "90 kg"
  [1] =>
  string(5) "92 kg"
  [2] =>
  string(6) "100 kg"
  [3] =>
  string(5) "94 kg"
  [4] =>
  string(5) "98 kg"
  [5] =>
  string(6) "125 kg"
} 


Or use array_column

Thanks a lot! I have easily solved my problem with your help