/**
 * Retireve count of collection loaded items
 *
 * @return int
 */
public function count()
{
    $this->load();
    return count($this->_items);
}

/**
 * Get collection size
 *
 * @return int
 */
public function getSize()
{
    if (is_null($this->_totalRecords)) {
        $sql = $this->getSelectCountSql();
        $this->_totalRecords = $this->getConnection()->fetchOne($sql, $this->_bindParams);
    }
    return intval($this->_totalRecords);
}

$collection = Mage::getModel('zzz/zzz')->getCollection();
var_dump($collection->getSize());

if (!$datas->getData() || empty($datas->getData())) {
     // do things
}

$collection = Mage::getModel('zzz/zzz')->getCollection();
var_dump($collection->count());

<?php
if(isset($pro_collection) && count($pro_collection) > 0) {
    /* Your code here */
}
?>