Question from the Magento test

[php]
$customer = Mage::getModel('customer/entity') ->loadByEmail('[email protected]');
[/php]

[php]
$collection = Mage::getModel('customer/customer')->getCollection();$customer = $collection -> addAttributeToFilter('email','[email protected]');
[/php]

[php]
$collection = Mage::getModel('customer/customer')->getCollection();$customer = $collection -> addFieldToFilter('email','[email protected]') -> setPage(1,1) -> getFirstItem();
[/php]

[php]
$collection = Mage::getModel('customer/customer')->getCollection();$collection ->getSelect() ->where('email=?', '[email protected]')->limit(1);
$customer =$collection->getLastItem();
[/php]