Notice: Undefined offset: 1, Undefined offset: 2

Question

I have some notice in a line 27 of the method bellow, and can't find the issue !

public function blockOrder()
{
    $items = Mage::getSingleton('checkout/cart')->getQuote()->getItemsCollection();
    $tab = array();
    foreach ($items as $itemCart) {
    /*line 27*/ $tab[$itemCart->getUdropshipVendor()] += $itemCart->getPrice() * $itemCart->getQty();
    }
    foreach ($tab as $vendorId => $amountInCart) {
        $vendorMinAmount = Mage::getModel('udropship/vendor')->load($vendorId)->getMinimumOrderAmount();
        if ($amountInCart < $vendorMinAmount) {
            return true;
        }
        return false;
    }
}

Answer 1

turn this

foreach ($items as $itemCart) {
    $tab[$itemCart->getUdropshipVendor()] += $itemCart->getPrice() * $itemCart->getQty();
}

into this

foreach ($items as $itemCart) {
    $vendor = $itemCart->getUdropshipVendor();
    if (!isset($tab[$vendor])) {
        $tab[$vendor] = 0;
    }
    $tab[$vendor] += $itemCart->getPrice() * $itemCart->getQty();
}