+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: General Coding Help (https://python-forum.io/forum-8.html)
+--- Thread: Run a Function?: Trouble with Online Python Course (/thread-37995.html)
Run a Function?: Trouble with Online Python Course - webmanoffesto - Aug-18-2022
Please help me with the below program. My Python is rusty. I'm trying to help my son with the below program. It should return a message like "Pichu (health: 30)", but it only returns nothing. Am I supposed to run a certain function?
What is missing?
class Pokemon():
def __init__(self):
self.name = ""
self.health = 0
def attack(self, other_pokemon):
raise NotImplementedError(
"Sorry, all subclasses have to write their own attack function!")
class Pichu(Pokemon):
def __init__(self):
self.name = "Pichu"
self.health = 30
def attack(self, other_pokemon):
other_pokemon.health -= 2
if other_pokemon.is_alive():
print("Pichu ZAPPED {}, dealing 2 damage [{}]".format(
other_pokemon.name, other_pokemon.health))
else:
print("Pichu ZAPPED {}, which faints".format(other_pokemon.name))
def is_alive(self):
if self.health > 0:
return True
else:
return False
return "{} (health: {})".format(self.name, self.health)
def __str__(self):
pass
RE: Run a Function?: Trouble with Online Python Course - Yoriz - Aug-18-2022
This part is not correct
return "{} (health: {})".format(self.name, self.health)
def __str__(self):
passthe __str__ method should return a stringchange it to
def __str__(self):
return "{} (health: {})".format(self.name, self.health)Then create an instance of Pichu and print itpichu = Pichu() print(pichu)
Output:Pichu (health: 30)RE: Run a Function?: Trouble with Online Python Course - webmanoffesto - Aug-18-2022
thank you! I'll try that
RE: Run a Function?: Trouble with Online Python Course - deanhystad - Aug-18-2022
I would use the abstract base class (abc) module. Declare "attack()" an abstract method and abc will raise an exception when you try to create an instance of an incomplete subclass instead of waiting to call the missing method. Plus you get a better error message.
import abc
class Pokemon(abc.ABC):
def __init__(self, name="", health=0):
# Using default arguments instead of hiding default values. Or don't use default arguments and
# force the user into providing values for name and health.
self.name = name
self.health = health
@abc.abstractmethod
def attack(self, other_pokemon):
"""Attack another pokemon"""
def is_alive(self):
return self.health > 0
def __str__(self):
return f"{self.name} (health: {self.health})"
class Pichu(Pokemon):
def __init__(self):
# Call superclass __init__(). Push up as much as you can to the superclass.
super().__init__("Pichu", 30)
def attack(self, other_pokemon):
other_pokemon.health -= 2
if other_pokemon.is_alive():
print(
"Pichu ZAPPED {}, dealing 2 damage [{}]".format(
other_pokemon.name, other_pokemon.health
)
)
else:
print("Pichu ZAPPED {}, which faints".format(other_pokemon.name))
class BadMonster(Pokemon):
"""I am not a proper subclass of Pokemon because I don't have an attack method"""
def __init__(self):
super().__init__("Bad Monster", -1)
p = Pichu()
b = BadMonster()Error:Traceback (most recent call last):
File "...", line 42, in <module>
b = BadMonster()
TypeError: Can't instantiate abstract class BadMonster with abstract method attackPush commonality up. is_alive() is likely something all Pokemon support, an likely it will be the same for all Pokemon. Put this in the base class. Same goes for __str__().
Use super(). As is, your code will never call Pokemon.__init__(). You can either drop that method from Pokemon, or you can call it from the subclass __init__() methods.
name and health should be arguments in Pokemon.__init__(). I provided default arguments, but you might want to make these required arguments to the init.