How to Simplify Loops with Exceptions for User Input?

py_coder1019 0
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I have the following code which works to input a new item into my dictionary into my list of dictionaries, as well as write it to the csv file.

Here is the following code:

def add_item(self):
       while True:
           try:
               item_num = int(input("What is the items #?\n"))
           except ValueError:
               print("That's not an int!")
               continue
           else:
               break
       while True:
           try:
               price = float(input("What is the items price?\n"))
           except ValueError:
               print("Thats not a float!")
               continue
           else:
               break
       while True:
           try:
               quant = int(input("What is the items quantity?\n"))
           except ValueError:
               print("Thats not an int!")
               continue
           else:
               break
       while True:
           try:
               name = str(input("What is the items name?\n"))
           except ValueError:
               print("Thats not a string!")
               continue
           if name == "":
               print("Ha! You have to enter a name!")
               continue
           else:
               break
       new_row = [item_num, price, quant, name]
       with open("Items2.csv", "a+") as  fp:
          reader = csv.reader(fp)
          fp.seek(0)
          labels = next(reader, None)
          writer = csv.writer(fp)
          new_record = dict(zip(labels, new_row))
          self.result.append(new_record)
          writer.writerow(new_record.values())
          print("Item Added! Check Inventory Again to see!")

I was wondering if there was a way to simplify this process and or shorten it? Obviously it is very repetitive, but I would like to keep using loops and exceptions, to make a user enter a correct input, and stay in that loop til they have. Is there any way to simplify this?

simplify exception loops python
1 Answers

One solution can be making a custom function that has two parameters: message and type of accepted input:

def enter_data(message, typ):
    while True:
        try:
            v = typ(input(message))
        except ValueError:
            print(f"That's not an {typ}!")
            continue
        else:
            break
    return v


def add_item():
    item_num = enter_data("What is the items #?\n", int)
    price = enter_data("What is the items price?\n", float)
    quant = enter_data("What is the items quantity?\n", int)

    while True:
        name = enter_data("What is the items name?\n", str)
        if name == "":
            print("Ha! You have to enter a name!")
            continue
        break

    new_row = [item_num, price, quant, name]
    print(new_row)


add_item()

Prints (for example):

What is the items #?
what?
That's not an <class 'int'>!
What is the items #?
3
What is the items price?
what?
That's not an <class 'float'>!
What is the items price?
10
What is the items quantity?
3
What is the items name?

Ha! You have to enter a name!
What is the items name?
Apple
[3, 10.0, 3, 'Apple']
Andrej Kesely0
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