Deletion of row from Item Details

for each  r in input.Item_Details
{
	b = ifnull(r.S_No,0) - 1;
	r.S_No=b;
	if(r.S_No < row.S_No)
	{
		b = b + 1;
		r.S_No=b;
	}
}
input.Gross_Total = ifnull(input.Gross_Total,0.0) - ifnull(row.Sub_Total,0.0);
input.Total_Quantity = ifnull(input.Total_Quantity,0.0) - ifnull(row.Qty,0.0);
if(input.Gross_Total == 0)
{
	input.Gross_Total = 0;
	input.Total_Quantity = null;
	input.Discount = null;
	input.Discount_Amount = 0;
	input.Discount_Amount = null;
	hide Discount_Amount;
	input.Discount_Percentage = null;
	hide Discount_Percentage;
	input.Final_Gross_Total = 0;
	input.Total_Taxes = null;
	input.Grand_Total = null;
	input.Gross_with_Discount = null;
	input.Gross_Value_Tax = null;
	input.Gross_Total_with_Discount = null;
	input.Packing_Forwarding = null;
	input.PF_Total_with_tax = null;
	input.PF_Tax_value = null;
}
for each  rec in input.Despatch_Schedule
{
	if(rec.Part_No == row.Part_No)
	{
		rec.Part_No=null;
		rec.Quantity=null;
		rec.Delivery_Date=null;
	}
}
itemlist = List();
qtyList = List();
dateList = List();
remarksList = List();
fullQtyList = List();
for each  rec in input.Despatch_Schedule
{
	if(rec.Part_No != null)
	{
		itemlist.add(rec.Part_No);
		qtyList.add(rec.Quantity);
		dateList.add(rec.Delivery_Date);
		remarksList.add(rec.Remarks);
		fullQtyList.add(rec.Full_Quantity);
	}
}
input.Despatch_Schedule.clear();
i = 0;
s_no = 0;
for each  items in itemlist
{
	s_no = s_no + 1;
	row1 = Sales_Order.Despatch_Schedule();
	row1.S_No=s_no;
	row1.Part_No=items;
	row1.Quantity=qtyList.get(i);
	row1.Delivery_Date=dateList.get(i);
	row1.Remarks=remarksList.get(i);
	row1.Full_Quantity=fullQtyList.get(i);
	input.Despatch_Schedule.insert(row1);
	i = i + 1;
}
//Grand total adjustment
input.Grand_Total = ifnull(input.Grand_Total,0.0) - ifnull(row.Total_Amount,0.0);