calculating the total of row 4 in excel csv file python
Question: I cant find the total of row 4 in a csv file my code is to enter a code which
is searched in a csv file which is then written to a new csv file in order for
it to be printed as a receipt my problem is in the last few lines this is my
code until know:

    
    
        import csv
    try_again= "Yes"
    myfile2=open("reciept.csv","a+")
    while try_again =="Yes":
        found= "no"
        myfile=open("stock_file.csv","r+")
        gtin_8= input("enter the gtin-8")
        quantity= input("enter quantity wanted")
        reader=csv.reader(myfile)
        for row in reader:
            if gtin_8 == row[0]:
                description= row[1]
                unit_price= row[2]
                product_price=((float(unit_price)*(float(quantity))))
                product_price1= str(product_price)
                new_record=(gtin_8+","+description+","+quantity+","+unit_price+","+product_price1)
                myfile2.write(str(new_record))
                myfile2.write("\n")
                found="yes"
    
        if found=="no":
            nf="not found"
            new_record1=(gtin_8+","+nf)
            myfile2.write(new_record1)
            myfile2.write("\n")
        try_again=input("do you want to try again")
        try_again=try_again.title()
    myfile2.close()
    myfile3=open("reciept.csv","r+")
    reader1=csv.reader(myfile3)
    total_cost=0
    for row in reader1:
        print (row)
        total = sum(float(r[4]) for r in csv.reader(myfile3))
    
    print (total_cost)
    


Answer: You have a nested loop at the end (for loop and a list comprehension inside
it) which is why it isn't working like you want it to.

You also define a variable named `total_cost` as `0` and never do anything
with it and then just print it.

No nested loop is needed so this should work:

    
    
    total_cost = 0.0
    for row in reader1:
        if row[1] == "not found"
            total_cost += float(row[4])
    

Other pointers:

There is a
[`csv.writer`](https://docs.python.org/3/library/csv.html#csv.writer) too
which is safer to use than just string concatenation and writing to a file.

