CodeIgniter difference in result_array when using while or foreach

Question

I have this function in my model:

public function get_current_knowledge($account_id)
{
    $query = $this->db->query('SELECT * FROM knowledge WHERE account_id = ?', array($account_id));

    return $query->result_array();
}

I used to access it like this:

while ($record = $this->synchronization_model->get_current_knowledge($account['id'])) {
    print_r($record);
}

But strangely, my page would timeout probably because the while results in a neverending loop or something? But why is the question.

I noticed that foreach does work. But essentially this should return the same as while right? When accessing it like this, using foreach:

foreach ($this->synchronization_model->get_current_knowledge($account['id']) as $row)
{
     print_r($row);
}

Jezen Thomas · Accepted Answer · 2013-01-25 19:47:58Z

1

The while() loop runs for as long as whatever is inside the parentheses is truthy.

You're assigning the value of $this->synchronization_model->get_current_knowledge($account['id']) to the variable $record every time the loop runs. Of course, the variable has a value (since you're assigning it), and so its always truthy. That's where you get your infinite loop.

answered Jan 25, 2013 at 19:47

Jezen Thomas

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4 Comments

edwardmp Over a year ago

But I used the while loop before I converted this code to codeigniter style. Like, while($record = pg_fetch_array(..) and in that time it used too work. I'm a bit confused.

Jezen Thomas Over a year ago

I think it would break out of the loop if $record was assigned a false value. It's hard for me to get the bigger picture of how your code previously behaved.

edwardmp Over a year ago

Yeah, I looked up pg_fetch_array on PHP.net. It returns false when the last row is returned. Apparently this does not happen when using the code I'm know using. Deciedd to switch to foreach where I previously used while. That should yield the same results right? Thanks for your help.

Jezen Thomas Over a year ago

Should do. You're welcome! Remember to mark my answer as correct if it helped you :)

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