The following array is stored in `$this->config->item('userlib_profile_fields')`

```
Array
(
[0] => Array
    (
        [first_name] => First Name
    )
[1] => Array
    (
        [family_name] => Family name
    )
[2] => Array
    (
        [web_address] => Web Address
    )
[3] => Array
    (
        [company_name] => Company Name
    )
...
...
)

```

I want to create an array from the above keys.

```
Array(first_name, family_name, web_address,company_name, .....)

```

I tried this but it give an errors.

```
$profile_columns = array();
foreach($this->config->item('userlib_profile_fields') as $value)
{
    foreach($value as $key=>$value)
    {
        //var_dump ($key);
        $profile_columns = array_push($profile_columns,$key);
    }
}
// error: array_push() expects parameter 1 to be array, integer given
array_push() expects parameter 1 to be array, null given

```