We Keep Coding

Complete the Car class by creating an attribute purchase_price (type int) and the method print_info() that outputs the car's information

class Car:
def __init__(self):
self.model_year = 0
# TODO: Declare purchase_price attribute
self.purchase_price = 0
self.current_value = 0
def calc_current_value(self, current_year):
depreciation_rate = 0.15
# Car depreciation formula
car_age = current_year - self.model_year
self.current_value = round(self.purchase_price * (1 - depreciation_rate) ** car_age)
# TODO: Define print_info() method to output model_year, purchase_price, and current_value
if __name__ == "__main__":
year = int(input())
price = int(input())
current_year = int(input())
my_car = Car()
my_car.model_year = year
my_car.purchase_price = price
my_car.calc_current_value(current_year)
my_car.print_info()
def print_info(self):
print("Car's information:")
print(" Model year:", self.model_year)
print("Purchase price:", self.purchase_price)
good day, I'm supposed to complete the car class, above is my current code, I am not sure how to fix the issue I keep getting the following error: my_car.print_info()
AttributeError: 'Car' object has no attribute 'print_info'
I have tried the above code, and also tried with this
def print_info(self):
print("Car's information:")
print(" Model year:", self.model_year)
print("Purchase price:", self.purchase_price)
I keep getting the same error. I am a beginner at this stuff so please help me understand.

it seems like your function is outside of the class. notice how you have a #TODO-- this is where you want to insert the function and be mindful of indentations.
Otherwise, your print function is fine.

As stated in the comments:
class Car:
def __init__(self):
self.model_year = 0
# TODO: Declare purchase_price attribute
self.purchase_price = 0
self.current_value = 0
def calc_current_value(self, current_year):
depreciation_rate = 0.15
# Car depreciation formula
car_age = current_year - self.model_year
self.current_value = round(
self.purchase_price * (1 - depreciation_rate) ** car_age)
# TODO: Define print_info() method to output model_year, purchase_price, and current_value
def print_info(self):
print("Car's information:")
print(" Model year:", self.model_year)
print("Purchase price:", self.purchase_price)
if __name__ == "__main__":
year = int(input())
price = int(input())
current_year = int(input())
my_car = Car()
my_car.model_year = year
my_car.purchase_price = price
my_car.calc_current_value(current_year)
my_car.print_info()
Input:
1
1
1
Output:
Car's information:
Model year: 1
Purchase price: 1

Shopping Program not displaying results accurately

I am creating a program that lets a user choose an item to buy, specify how many units they want to purchase, adds the items to the users cart, and then gives a summary of the users cart when they are finished shopping.
I am currently having two problems:
I need to decrement the units available for purchase based on whatever quantity the user selects during checkout. For example, if the user purchases 2 shirts, the menu will print again and show that the units available decreased from 20 to 18.
In my cart summary, I am having trouble figuring out how to get the total price based on the quantity of whatever items the user chose.
I need to display they number of items left in the cart after the cart is cleared. I have tried using count() but received an AttributeError. Essentially, I just need to make sure the print statement looks like this "Number of items left in Cash Register: 0".
RetailItem class:
class RetailItem:
def __init__(self, description = '', units = 0, price = 0.0):
self.__description = description
self.__units = units
self.__price = price
def __str__(self):
displayString = (f'{"Descirption":10}{self.__desciption}\n'
f'{"Inventory":10}{self.__units:15}\n'
f'{"Price":10}{self.__price:<15.2f}\n')
return displayString
#property
def description(self):
return self.__description
#description.setter
def description(self, d):
self.__description = d
#property
def units(self):
return self.__units
#units.setter
def units(self, u):
self.__units = u
#property
def price(self):
return self.__price
#price.setter
def price(self, p):
self.__price = p
#property
def price(self):
return self.__price
#price.setter
def price(self, p):
self.__price = p
CashRegister class:
class CashRegister:
def __init__(self):
self.__item = []
def purchase_item(self, item):
self.__item.append(item)
def get_total(self):
total = 0.0
for item in self.__item:
total += (item.price * item.units)
return total
def show_items(self):
for item in self.__item:
print(f'{item.description}, units: {item.units}, price: {item.price}')
def clear(self):
for item in self.__item:
self.__item.remove(item)
def __str__(self):
return f'Listed Item: {self.__item}'
MakePurchase.py:
from RetailItem import RetailItem as ri
from CashRegister import CashRegister as cr
def showMenu():
jacket = ri('Jacket', 12, 59.95)
jeans = ri('Designer Jeans', 40, 34.95)
shirt = ri('Shirt', 20, 24.95)
register = cr()
choice = '1'
while choice != '0':
print('\n**Menu**')
print(f'{"Choice"}{"Description":>19} {"Price":>20} {"Stock":>21}')
print(f'{"======"}{"===========":>19} {"=====":>20} {"=====":>21}')
print(f'{"1"}{jacket.description:>19} {jacket.price:>25} {jacket.units:>18}')
print(f'{"2"}{jeans.description:>19} {jeans.price:>26} {jeans.units:>18}')
print(f'{"3"}{shirt.description:>19} {shirt.price:>26} {shirt.units:>18}')
print(f'{"======"}{"===========":>19} {"=====":>20} {"=====":>21}')
choice = input('Insert your choice or 0 to exit: ')
if choice == '0':
showCart(register)
elif choice == '1':
quantity = input('Insert quantity: ')
register.purchase_item(jacket)
elif choice == '2':
quantity = input('Insert quantity: ')
register.purchase_item(jeans)
elif choice == '3':
quantity = input('Insert quantity: ')
register.purchase_item(shirt)
else:
print('That item is not available')
def showCart(register):
print('\nCart')
print('====')
print(f'{register.show_items()}')
print('====')
print(f'Total Price: {register.get_total():.2f}')
print('============')
print('\nClearing cash register...')
print('\nNumber of items left in Cash Register: ',) #NEED TO GET NUMBER OF ITEAMS LEFT IN CART
print(register.clear())
def main():
showMenu()
if __name__ == '__main__':
main()
SAMPLE OUTPUT:
**Menu**
Choice Description Price Stock
====== =========== ===== =====
1 Jacket 59.95 12
2 Designer Jeans 34.95 40
3 Shirt 24.95 20
====== =========== ===== =====
Insert your choice or 0 to exit: 3
Insert quantity: 2
**Menu**
Choice Description Price Stock
====== =========== ===== =====
1 Jacket 59.95 12
2 Designer Jeans 34.95 40
3 Shirt 24.95 20
====== =========== ===== =====
Insert your choice or 0 to exit: 0
Cart
====
Shirt, units: 20, price: 24.95 #UNITS SHOULD BE 2
None #NOT SURE HOW TO PREVENT THIS FROM PRINTING
====
Total Price: 499.00 #SHOULD BE 49.90
============
Clearing cash register...
Number of items left in Cash Register: #SHOULD BE 0 INSTEAD OF NONE
None

How to store the total withdrawn amount for each category obejct? [duplicate]

I have a Category class and there is a ledger attribute for each instance of this class. This ledger attribute is actually a list of dictionaries which contain the withdrawal and deposit amounts and descriptions in the form {"amount" : amount, "description" : description}. Now, I want to define a function create_spend_chart which will take a list of objects as the parameter, and will find the total amount of withdrawals. I have been able to do this successfully:
def create_spend_chart(categories):
total_withdrawn = 0
for i in categories:
for p in i.ledger:
if p["amount"] < 0:
total_withdrawn += -p["amount"]
But the problem I'm facing here is, I can't seem to store the total withdrawal amount for each category object separately. How can I do this?
My code-base might help you ins answering the question:
class Category:
def __init__(self, name):
self.name = name
self.ledger = list()
def get_balance(self):
total_balance = 0
for i in self.ledger:
total_balance += i["amount"]
return total_balance
def check_funds(self, amount):
if self.get_balance() >= amount:
return True
else:
return False
def deposit(self, amount, description = "Deposit"):
form = {"amount" : int(amount), "description" : description}
self.ledger.append(form)
def withdraw(self, amount, description = "Withdrawal"):
if description == None:
description = "Withdrawal"
form = {"amount" : -int(amount), "description" : description}
if self.check_funds(amount):
self.ledger.append(form)
return True
else:
return False
def transfer(self, amount, category_object):
form1 = {"amount" : -int(amount), "description" : f"Transfer to {category_object.name}"}
form2 = {"amount" : int(amount), "description" : f"Transfer from {self.name}"}
if self.check_funds(amount):
self.ledger.append(form1)
category_object.ledger.append(form2)
return True
else:
return False
def __repr__(self):
Ledger = ""
for i in self.ledger:
if len(i["description"]) > 23:
des = i["description"][:23]
else:
des = i["description"]
Ledger += des.ljust(23) + str(round(i["amount"], 2)).rjust(7) + "\n"
Ledger = Ledger + "Total: " + str(round(self.get_balance(), 2))
receipt = f"{self.name}".center(30, "*") + "\n" + Ledger
return receipt
def create_spend_chart(categories):
total_withdrawn = 0
withdrawals = list()
for i in categories:
for p in i.ledger:
if p["amount"] < 0:
total_withdrawn += -p["amount"]
PS: This function is not a method, it is defined outside of the class declaration.

Use a collections.defaultdict to make aggregations such as that easy as pie.
import collections
# ...
withdrawn_per_category = collections.defaultdict(int)
for i in categories:
for p in i.ledger:
if p["amount"] < 0:
withdrawn_per_category[i.name] += -p["amount"]
(I've opted to use int as the default data type, but it doesn't truly matter here, so long as it's a conversible numeric type.)
Without collections
If for some reason you don't want to use the handy, built-in collections module, you can emulate the same behavior yourself with a regular dict:
withdrawn_per_category = {}
for i in categories:
for p in i.ledger:
if p["amount"] < 0:
withdrawn_per_category[i.name] = withdrawn_per_category.get(i.name, 0) - p["amount"]

Python Product Inventory

I'm working on a simple product inventory which essentially allows user to add products, display them and deduce the inventory value. I am stuck in the part where the inventory value is deduced. What I want the code to do here is multiply the product price * product quantity for each added product and return the sum. When I run the code, I get the error, TypeError: 'int' object is not iterable. I am new at Python, would appreciate any guidance!
Here is a portion of the code:
class Product:
def __init__(self, idnum, price, quantity):
self.idnum = idnum
self.price = price
self.quantity = quantity
class Inventory:
def __init__(self):
self.productlist = []
def add_product(self):
idnum = int(input('Enter id: '))
price = int(input('Enter price: '))
quantity = int(input('Enter quantity: '))
self.productlist.append(Product(idnum, price, quantity))
return self.productlist
def display(self):
for product in self.productlist:
print(product.idnum, product.price, product.quantity)
def inventory_value(self):
for product in self.productlist:
return sum(product.price*product.quantity)

I think you meant to sum all the products (the result of multiplication) like that:
def inventory_value(self):
running_sum = 0
for product in self.productlist:
running_sum += product.price * product.quantity
return running_sum
Or simply:
def inventory_value(self):
return sum(product.price * product.quantity for product in self.productlist)
Notice that this `sums over a collection, and not a single integer, like in your case:
>>> [x * (x + 1) for x in range(5)]
[0, 2, 6, 12, 20]
>>> sum(x * (x + 1) for x in range(5))
40

Search within a dictionary with a lot of values in python

In the following code I'm showing a function that lets you add students to a dictionary (book) with rut being the key, the issue I have is that I'm trying to make a function that can search by department and then print all students of that are part of that department, basically I'm asking how do you search a dictionary with 1 key that is associated to a lot of values and you want to search for a particular value and then print all keys that have it along with their info?
book = {}
def add(rut, name, age, department):
student = {}
student['rut'] = rut
student['name'] = name
student['age'] = age
student['department'] = department
book[rut] = student
def printall():
for rut in book:
student = book[rut]
print(student['rut'], student['name'], student['age'], student['department'])
def main():
count = 0
x = 0
y = int(input("How many students will you add?: "))
while count < y:
print('Input data of the student: ', count+1)
rut = input("rut: ")
name = input("name: ")
age = int(input("age: "))
print("Department 1: RH, 2: Logistic, 3: Cleaners, 4: TI ")
department = ''
while x == 0:
num_dept = int(input("department number: "))
if num_dept == 1:
department = "RH"
x = 1
elif num_dept == 2:
department = "Logistic"
x = 1
elif num_dept == 3:
department = "Mathematics"
x = 1
elif num_dept == 4:
department = "TI"
x = 1
else:
print('Error')
x = 0
add(rut, name, age, department)
count = count + 1
printall()
main()

You can use a list comprehension.
students = [student for student in book.values()
if student["department"] == desired_department]
This will give you a list, which you can then print out if you so choose.