In OOP in python, are different instances of an object when initialised with a default value the same? - python-3.x

I am trying to understand object oriented programming. I am doing this by creating a small poker like program. I have come across a problem whose minimal working example is this:
For this code:
import random
class superthing(object):
def __init__(self,name,listthing=[]):
self.name = name
self.listthing = listthing
def randomlyadd(self):
self.listthing.append(random.randint(1,50))
def __str__(self):
return '\nName: '+str(self.name)+'\nList: '+str(self.listthing)
Aboy = superthing('Aboy')
Aboy.randomlyadd()
print(Aboy)
Anotherboy = superthing('Anotherboy')
Anotherboy.randomlyadd()
print(Anotherboy)
I expect this output :
Name: Aboy
List: [44]
(some number between 1 and 50)
Name: Anotherboy
List: [11]
(again a random number between 1 and 50)
But what I get is:
Name: Aboy
List: [44]
(Meets my expectation)
Name: Anotherboy
List: [44,11]
(it appends this number to the list in the previous instance)
Why is this happening? The context is that two players are dealt a card from a deck. I am sorry if a similar question exists, if it does, I will read up on it if you can just point it out. New to stack overflow. Thanks in advance.
For the non minimal example, I am trying this:
import random
class Card(object):
def __init__(self, suit, value):
self.suit = suit
self.value = value
def getsuit(self):
return self.suit
def getval(self):
return self.value
def __str__(self):
if(self.suit == 'Clubs'):
suitstr = u'\u2663'
elif(self.suit == 'Diamonds'):
suitstr = u'\u2666'
elif(self.suit == 'Hearts'):
suitstr = u'\u2665'
elif(self.suit == 'Spades'):
suitstr = u'\u2660'
if((self.value<11)&(self.value>1)):
valuestr = str(self.value)
elif(self.value == 11):
valuestr = 'J'
elif(self.value == 12):
valuestr = 'Q'
elif(self.value == 13):
valuestr = 'K'
elif((self.value == 1)|(self.value == 14)):
valuestr = 'A'
return(valuestr+suitstr)
class Deck(object):
def __init__(self,DeckCards=[]):
self.DeckCards = DeckCards
def builddeck(self):
suits = ['Hearts','Diamonds','Clubs','Spades']
for suit in suits:
for i in range(13):
self.DeckCards.append(Card(suit,i+1))
def shuffle(self):
for i in range(len(self)):
r = random.randint(0,len(self)-1)
self.DeckCards[i],self.DeckCards[r] = self.DeckCards[r],self.DeckCards[i]
def draw(self):
return self.DeckCards.pop()
def __str__(self):
return str([card.__str__() for card in self.DeckCards])
def __len__(self):
return len(self.DeckCards)
class Player(object):
def __init__(self,Name,PlayerHandcards = [],Balance = 1000):
self.Name = Name
self.Hand = PlayerHandcards
self.Balance = Balance
def deal(self,deck):
self.Hand.append(deck.draw())
def __str__(self):
return 'Name :'+str(self.Name)+'\n'+'Hand: '+str([card.__str__() for card in self.Hand])+'\n'+'Balance: '+str(self.Balance)
deck1 = Deck()
deck1.builddeck()
deck1.shuffle()
Alice = Player('Alice')
Alice.deal(deck1)
print(Alice)
Bob = Player('Bob')
Bob.deal(deck1)
print(Bob)
And after dealing to Bob they both have the same hands. If you have some other suggestions regarding the code, you are welcome to share that as well.

This is a duplicate of “Least Astonishment” and the Mutable Default Argument as indicated by #Mad Physicist. Closing this question for the same.

Related

Why the type of a parameter of a function in a class would change into list?

class Employee:
num_of_emps = 0
raise_amount = 1.04
def __init__(self, first, last, pay):
self.first = first
self.last = last
self.pay = pay
self.email = first + last + '#gmail.com'
Employee.num_of_emps += 1
def fullname(self):
return f'I am {self.first} {self.last}'
def apply_raise(self):
self.pay = int(self.pay * Employee.raise_amount)
#classmethod
def set_raise_amt(cls, amount):
cls.raise_amount = amount
#classmethod
def from_string(cls, emp_str):
first, last, pay = emp_str.split('-')
return cls(first, last, pay)
#staticmethod
def is_workday(day):
if day.weekday() == 5 or day.weekday() == 6:
return False
return True
class Developer(Employee):
raise_amount = 1.50
def __init__(self, first, last, pay, prog_lang):
super().__init__(first, last, pay)
self.prog_lang = prog_lang
class Manager(Employee):
def __init__(self, first, last, pay, employees=None):
super().__init__(first, last, pay)
if employees is None:
self.employees = []
else:
self.employees = employees
def add_emp(self,emp):
if emp not in self.employees:
self.employees.append(emp)
def remove_emp(self,emp):
if emp in self.employees:
self.employees.remove(emp)
def print_emps(self):
for emp in self.employees:
print('--->', emp.full_name())
dev_1 = Developer('John','Doe',30000, 'Python')
dev_2 = Developer('Emily','Smith',23000, 'Java')
# print(help(Developer))
print(dev_1.email)
print(dev_2.email)
print(dev_1.pay)
dev_1.apply_raise()
print(dev_1.pay)
mgr_1 = Manager('Sarah','Smith',34000, [dev_1])
print(type(mgr_1.employees))
print(mgr_1.employees)
print(type(dev_1))
print(type([dev_1]))
print([dev_1])
mgr_1.print_emps()
I recently studied this code on youtube. So basically this code started with a class named 'Employee' at the beginning, and then a subclass called 'Developer' was created. I still able to catch up with the logic behind the code at the moment, but after another subclass called 'Manager' was created, I lost.
I don't know why the parameter,'employees' in the class 'Manager' would suddenly become a list in the end
And I also don't know why the for loop could be able to run
Please help, thank you so much
mgr_1 = Manager('Sarah','Smith',34000, [dev_1])
first='Sarah', last='Smith', pay=34000, employees=[dev_1]
Your parameter is an list

How can I print the method from within a Class?

I have created two separate classes with the intent of creating instances of those Classes and accessing the methods within the Classes. However, when I run this code, I cannot print out the list of grades in the print.grades method.
'''
class Student:
def __init__(self, name, year):
self.name = name
self.year = year
self.grades = []
def add_grade(self, grade):
if type(grade) == Grade:
self.grades.append(grade)
else:
pass
def get_average(self):
sum_score = 0
for i in self.grades:
sum_score += i
ave = sum_score / len(grades)
return ave
def print_grades(self):
for i in self.grades:
print(i)
roger = Student("Roger van der Weyden", 10)
sandro = Student("Sandro Botticelli", 12)
pieter = Student("Pieter Bruegel the Elder", 8)
class Grade:
def __init__(self, score):
self.score = score
def is_passing(self, grade):
if grade >= self.minimum_passing:
return "Passing!"
else:
return "Not Passing"
minimum_passing = 65
new_Grade = Grade(100)
pieter.add_grade(new_Grade)
print(new_Grade.is_passing(100))
pieter.add_grade(90)
pieter.add_grade(100)
pieter.print_grades
'''

How in Pyhton's OOP a class's method access to another class's method?

I am new to Python OOP and I am trying to learn the basics of Python OOP and I came across a video on YouTube that teaches the basics of it. The code is an example code from the video. I understood all of it but I am not able to understand how the class "Course's" "get_average_grade()" method is accessing the class "Student's" "get_grade()" method? Any help is highly appreciated.
class Student:
def __init__(self, name, age, grade):
self.name = name
self.age = age
self.grade = grade # 0-100
def get_grade(self): #<---- This method was used inside the Course class
return self.grade
class Course:
def __init__(self, name, max_students):
self.name = name
self.max_students = max_students
self.students = []
def add_student(self, student):
if len(self.students) < self.max_students:
self.students.append(student)
return True
return False
def get_average_grade(self):
value = 0
for student in self.students:
value = value + student.get_grade() #<---- This Method is from the Student class
return value / len(self.students)
s1 = Student("Tim", 19, 95)
s2 = Student("Bill", 19, 75)
s3 = Student("Jill", 19, 65)
course = Course("Science", 2)
course.add_student(s1)
course.add_student(s2)

how to access to data from a class which is stored in another class in python?

This is my code. I got a problem when i want to print the information inside the class 'pokemon'
class trainer(object):
def __init__(self, name, pokemons = [], money = 0):
self.name = name
self.pokemons = pokemons
self.money = money
this is my first class which has every pokemon per trainer
class pokemon(object):
def __init__(self, name, attribute, attacks = {}, health = '==========='):
self.name = name
self.attribute = attribute
self.health = health
self.attacks = attacks
The other class where I take the pokemon to import to the other class
class fight():
def __init__(self, fighter1, fighter2):
self.fighter1 = fighter1
self.fighter2 = fighter2
def fighting(self):
if len(Trainer1.pokemons) >= 1 and len(Trainer2.pokemons) >= 1:
print('{} wanna fight against {}'.format(Trainer1.name, Trainer2.name))
keepgoing = True
print('{} got this Pokemons: '.format(Trainer1.name))
i = 0
for i in Trainer1.pokemons:
print(i)
#while (keepgoing):
else:
print('You gotta have pokemons to fight')
return False
I thought that creating a class named fight for getting in battle would be the most wise idea but I'd like to know another method to do it
Pokemon1 = pokemon('Charizard', 'Fire', attacks={'1':'ball fire', '2':'cut', '3':'fire blast', '4':'mega kick'})
Pokemon2 = pokemon('Charmander', 'fire', attacks={'1':'blast', '2':'scratch', '3':'heat', '4':'tear'})
Trainer1 = trainer('Santiago', pokemons=[Pokemon1, Pokemon2])
Pokemon3 = pokemon('Charizard', 'Fire', attacks={'1':'ball fire', '2':'cut', '3':'fire blast', '4':'mega kick'})
Pokemon4 = pokemon('Charmander', 'fire', attacks={'1':'blast', '2':'scratch', '3':'heat', '4':'tear'})
Trainer2 = trainer('Alejandra', pokemons=[Pokemon3, Pokemon4])
Okay my problem is in the class fight. when i want to print the names of the pokemons i get the following message:
Santiago got this Pokemons:
<__main__.pokemon object at 0x000002AAD9B64D00>
<__main__.pokemon object at 0x000002AAD9B92DF0>
i know that the pokemon class has various instances, but how can i access to them?
To make your life easier, I recommend that you implement the __str__ dunder method on pokemon. This will resolve the issue that you are seeing right now, and make future prints of pokemon much easier.
That would look something like this:
class pokemon(object):
def __init__(self, name, attribute, attacks = {}, health = '==========='):
self.name = name
self.attribute = attribute
self.health = health
self.attacks = attacks
def __str__(self):
return "Pokemon: %s (Health: %11s)" % (self.name, self.health)
When you print the 'Charmander' pokemon, it'll look something like this:
Pokemon: Charmander (Health: ===========)
Of course, you can change the return of the __str__ to return whatever you want out of the pokemon.

getting all attributes of an object python 3

I read all questions and answers about this but none seems to help , using var from one of the answers was close but i need to use the same function with different objects. What should i change in the function so i don't have to make multiple functions for each object, i mean say i have another objects Human , Plants do i have to make a function for each one just changing the animal syntax:
class Animal(object):
def __init__(self):
self.legs = 2
self.name = 'Dog'
self.color= 'Spotted'
self.smell= 'Alot'
self.age = 10
self.kids = 0
def get_info(self) :
if __name__ == '__main__':
animal = Animal()
temp = vars(animal)
for item in temp:
print(item , ' : ' , temp[item])
Instead of hard coding the variable you should do this:
class Animal(object):
def __init__(self, legs, name, color, smell, age, kids):
self.legs = legs
self.name = name
self.color= color
self.smell= smell
self.age = age
self.kids = kids
if __name__ == '__main__':
animal = Animal(2, 'Dog', 'Spotted', 'Alot', 10, 0)
temp = vars(animal)
for item in temp:
print(item , ' : ' , temp[item])
i figured it out all i had to do was assigning user input to a variable then call it from objects like this :
class Animal(object):
def __init__(self):
self.legs = 2
self.name = 'Dog'
self.color= 'Spotted'
self.smell= 'Alot'
self.age = 10
self.kids = 0
noun = input()
def get_info(noun) :
if __name__ == '__main__':
character = Object.objects[noun]
temp = vars(character)
for item in temp:
print(item , ' : ' , temp[item])

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