Magento Collection, how to obtain array of values of a particular field

Question

Starting from a Collection, I need to obtain an array of values of a particular field..let me call this field my_id.

To do this, I use the Varien_Data_Collection::setDataToAll() on my Collection..in this way:

$collection_fields_array = $collection->setDataToAll(array('my_id'))->toArray(array('my_id'));

..what I obtain is something like this:

Array
(
    [0] => Array
        (
            [my_id] => 71e1bd18
        )

    [1] => Array
        (
            [my_id] => 70d47a69
        )

    [2] => Array
        (
            [my_id] => 687bed84
        )

    [3] => Array
        (
            [my_id] => 673df159
        )

    [4] => Array
        (
            [my_id] => 66690a4c
        )

    [5] => Array
        (
            [my_id] => 65994440
        )
)

But..if my Collection contains a large number of items..setDataToAll() becomes too time consuming and finally crashes all 2Gb(!!!) of memory...this is because its iteration between all items.

Is another way to obtain an array of field values without this workaround?

Answer 1

In this case,you can use getColumnValues('fieldName').

So,try this

$collection->getColumnValues('my_id')