Not sure if this is what your looking for, but to get one data-field of a large collection you can use $collection->getColumnValues('attribute_code').

Edit:

How do you do when you want to know the data present in some object that you don't know what it contains ?

When talking about debugging large objects you can also use this

# if $item is some kind of Varien object
Mage::log($item->debug());

Not sure if this is what your looking for, but to get one data-field of a large collection you can use $collection->getColumnValues('attribute_code').

Edit:

How do you do when you want to know the data present in some object that you don't know what it contains ?

When talking about debugging large objects you can also use this. It will leave out any recursive data - so you'll get no blank screen or empty log file for large objects ...

# if $item is some kind of Varien object
Mage::log($item->debug());

Not sure if this is what your looking for, but to get one data-field of a large collection you can use $collection->getColumnValues('attribute_code').

Not sure if this is what your looking for, but to get one data-field of a large collection you can use $collection->getColumnValues('attribute_code').

Edit:

How do you do when you want to know the data present in some object that you don't know what it contains ?

When talking about debugging large objects you can also use this

# if $item is some kind of Varien object
Mage::log($item->debug());