Inheriting class attributes without declaring attributes or better OOP - python

I am attempting to construct classes to play out a game of MTG (A card game). I have three relevant classes: MTGGame(...), MTGCard(...), and AbilityList(). An object of MTGGame has several attributes about the player (turn, mana,..., deck).
A player must have a deck of cards to play, so I create a list of MTGCard objects for each player that is a deck, and create an MTGGame object for each from the respective decks. The cards have abilities, and when creating the cards I store abilities as functions/params into each MTGCard. However, I need the abilities to inherit and access methods/attributes from MTGGame and update them, but if I use super().__init__, then I will need to call my deck as a parameter for AbilityList when making MTGCards, which I wouldn't have yet.
Can this be achieved? If not, any suggestions improving my OOP logic to achieve this task?
I am aware that I can do something like this:
class MTGGame():
def __init__(self, deck, turn = 0, mana = 0, lifeTotal = 20, cavalcadeCount = 0, hand = [], board = []):
self.turn = turn
self.mana = mana
self.lifeTotal = lifeTotal
...
def gainLife(self, lifeGained):
self.lifeTotal = self.lifeTotal +lifeGained
def combatPhase(self):
for card in self.board:
card.attackingAbility()
class MTGCard():
def __init__(self, name, CMC, cardType, power, toughness, castedAbility, attackingAbility, activatedAbility, canAttack = False):
....
self.attackingAbility = attackingAbility
Class abilityList():
def healersHawkAbility(self, lifeAmt):
MTGGame.gainLife(lifeAmt)
But this would affect all instances of MTGGame, not the specific MTGGame object this would've been called from. I'd like it to simply update the specific object in question. I'd like to do something like this but I don't know how abilityList methods could access MTGGame attributes/methods ('AbilityList' object has no attribute 'gainLife'):
Class abilityList():
def healersHawkAbility(self, lifeAmt):
#How do I access methods/attributes in MTGGame from here? self?
self.gainLife(lifeAmt)
aL = abilityList()
#One example card:
card1 = MTGCard("Healers Hawk",1,'Creature',1,1, aL.nullAbility(), aL.healersHawkAbility, aL.nullAbility())
whiteDeck = [list of constructed MTGCard() objects, card1, card2,...,cardLast]
player1 = MTGGame(whiteDeck)
...
#Call the ability in a method contained in MTGGame:
player1.combatPhase()
#Would call something like this inside
card.attackingAbility()
#Which may refer to card.healersHawkAbility() since we stored healersHawkAbility() as an attribute for that MTGCard,
#and would declare gainLife(), which refers to self.lifeTotal or player1.lifeTotal in this case.

This is an excellent start and clearly you have already thought a lot of this through. However, you haven't thought through the relationship between the classes.
First thing to note:
MTGGame.gainLife(lifeAmt) is a method call accessed via the class rather than an instance. This means that the self paramter is not actually filled in i.e. you will get an error becuase your method expects 2 arguments but only receive one.
What you perhaps meant to do is the following:
class MTGGame:
lifeTotal = 20 # Notice this is declared as a class variable
def __init__(self, ...):
...
#classmethod
def healersHawkAbility(cls, lifeGained):
cls.lifeTotal = cls.lifeTotal + lifeGained
However, this requires class variables which here defeats the point of having an instance.
Your naming throughout the program should suggest that your classes are a little off.
For instance player1 = MTGGame(). Is player a game? No, of course not. So actually you might want to rename your class MTGGame to Player to make it clear it refers to the player, not the game. A seperate class called MTGGame will probably need to be created to manage the interactions between the players e.g. whose turn it is, the stack holding the cards whilst resolving.
The main focus of your question: how to deal with the cards accessing the game/player object.
Cards should be able to access instances of the player and game classes, and if the player has a is_playing attribute, the card should not have this. The rule of thumb for inheritance is 'is a'. Since card 'is not a' player, it should not inherit from it or MTGGame. Instead, card should be like this for example:
game = RevisedMTGGame()
player1 = Player()
player2 = Player()
class Card:
def __init__(self, name, text, cost):
self.name = name
self.text = text
self.cost = cost
self.owner = None
self.game = None
class Creature(Card):
def __init__(self, name, text, cost, power, toughness):
super().__init__(self, name, text, cost)
self.power = power
self.toughness = toughness
def lifelink(self):
self.owner.heal(self.power) # NOTE: this is NOT how I would implement lifelink, it is an example of how to access the owner
healersHawk = Creature("Healer's Hawk", "Flying, Lifelink", 1, 1, 1)
healersHawk.game = game
healersHawk.owner = player1
You can see from this incomplete example how you can set up your cards easily, even with complex mechanics, and as the base classes have been defined you can avoid repitition of code. You might want to look into the event model in order to implement the lifelink mechanic, as an example. I wish you luck in continuing your game!

Related

Better way to create my lists in classes?

I've been working on making my text based game more realistic, and one design I would like to implement is to make sure the rooms stay 'static' to a point (i.e. a player uses a potion in the room, if they come back to that room that potion should no longer be there.)
This is how my code is basically set up (I have been using "Learn Python The Hard Way" by Zed Shaw so my code is set up much in the same way):
class Scene(object):
def enter(self):
print "This scene is not yet configured. Subclass it and implement enter()."
class Room(Scene):
potions = []
for i in range(3):
potions.append(Potion())
def enter(self):
...
When I run this, I get a NameError: global name 'potions' is not defined. I know I can fix this one of two ways: 1. make potions a global variable, but then I would have to make a new list for each room that contains potions (There are 36 rooms in total, set up as a 6x6 grid) OR
2. Put this line of code in the enter function, but that would cause the list to reset to 3 potions each time the user enters the room.
potions = []
for i in range(3):
potions.append(Potion())
If there's no other way, I suppose declaring a new variable for all the rooms that contain potions (There's only 5). But my question is if there's another way of making this work without making it a global.
Thanks for your help!
First, let's look at your example (I'll simplify it):
class Room(Scene):
potions = [Potion() for x in range(3)]
What you have done there is create a class attribute potions that are shared among all instances of Room. For example, you'll see my potions in each of my rooms are the same instances of potions (the hex number is the same!). If I modify the potions list in one instance, it modifies the same list in all of the Room instances:
>>> room1.potions
[<__main__.Potion instance at 0x7f63552cfb00>, <__main__.Potion instance at 0x7f63552cfb48>, <__main__.Potion instance at 0x7f63552cfb90>]
>>> room2.potions
[<__main__.Potion instance at 0x7f63552cfb00>, <__main__.Potion instance at 0x7f63552cfb48>, <__main__.Potion instance at 0x7f63552cfb90>]
>>>
It sounds like you want potions to be a unique attribute of each instance of a Room.
Somewhere you will be instantiating a room, e.g., room = Room(). You need to write your constructor for your Room in order to customize your instance:
class Room(Scene):
def __init__(self): # your constructor, self refers to the Room instance.
self.potions = [Potion() for x in range(3)]
Now when you create your room instance, it will contain 3 potions.
You now need to think about how you will make your rooms instances persist between entrances by your characters. That will need to be some sort of variable that persists throughout the game.
This idea of object composition will extend through your game. Perhaps you have a Dungeon class that has your 36 rooms:
class Dungeon(object):
def __init__(self):
self.rooms = [[Room() for x in range(6)] for x in range(6)]
Or perhaps your rooms have up to four doors, and you link them up into something potentially less square:
class Room(Scene):
def __init__(self, north_room, east_room, south_room, west_room):
self.north_door = north_room
self.east_door = east_room
[... and so on ...]
# Note: You could pass `None` for doors that don't exist.
Or even more creatively,
class Room(Scene):
def __init__(self, connecting_rooms): # connecting_rooms is a dict
self.connecting_rooms = connecting_rooms
Except both examples will get you a chicken and egg problem for connecting rooms, so it is better to add a method to add each room connection:
class Room(Scene):
def __init__(self):
self.rooms = {}
# ... initialize your potions ...
def connect_room(self, description, room):
self.rooms[description] = room
Then you could do:
room = Room()
room.connect_room("rusty metal door", room1)
room.connect_room("wooden red door", room2)
room.connect_room("large hole in the wall", room3)
Then perhaps your dungeon looks like this:
class Dungeon(Scene):
def __init__(self, initial_room):
self.entrance = initial_room
Now in the end, you just have to hold onto your dungeon instance of Dungeon for the duration of the game.
btw, this construct of "rooms" connected by "paths" is called a Graph.

Questions about pulling object information from subclasses

my apologies if there are similar questions in regards to mine. I'm rather new to Python, and still getting used to OOP. That being said, if one of the many kind souls in this community could help in regards to my specific situation, or point me in the direction of similar questions that have been asked, -- though I'd like to note that Googling was no help and each question w/ similar errors were so widely different, and spanned so many different projects, I had a hard time grasping the solutions -- it would be greatly appreciated.
Let's say I have a file named 'objects.py' to store most of my class objects for a text based game I'm developing, and in that file I have a class named 'Occupation'. Class 'Occupation' holds variables that are used as modifiers for the 'Player' class that will be described a little more later on.
The idea is that in the root file, namely 'root.py', the player will be able to choose from a list of player occupations, e.g. 'wizard' or 'knight', and have the information from the respective Occupation classes replace the current Player variable information.
'player.py' file:
import objects
class Player(object):
nextlevel = 30
# 'nextlevel' is the gold required for a level up.
def __init__(self):
self.name = ''
self.level = 1
self.health = 1
self.stamina = 0
self.mana = 0
self.skills = {'str': 0, 'def': 0, 'dex': 0, 'int': 0, 'chr': 0, 'lck': 0}
self.spells = []
self.inventory = [{'armor': [objects.PrisonerRobes()], 'weapons': [objects.IronDagger()], 'bows': [], 'potions': [], 'misc': []}, objects.Gold(0), objects.Arrow(0)]
self.victory = False
'objects.py' file:
class Occupation(object):
# Base class for all occupations / classes, e.g. 'knight' or 'wizard'.
classlist = ['warrior', 'knight', 'paladin', 'druid', 'warlock', 'wizard']
def __init__(self, name, hp, sp, mp, strv, defv, dexv, intv, chrv, lckv):
# The variable names of 'strv', 'defv', etc. stand for 'strength value', 'defence value', etc.
self.name = name
self.health = health
self.stamina = stamina
self.mana = mana
self.strv = strv #skill values
self.defv = defv
self.dexv = dexv
self.intv = intv
self.chrv = chrv
self.lckv = lckv
def __str__(self):
details = '{0}: HP: {1}, SP: {2}, MP: {3} // [STR: {4}, DEF: {5}, DEX: {6}, INT: {7}, CHR: {8}, LCK: {9}]'
return details.format(self.name, self.health, self.stamina, self.mana, self.strv, self.defv, self.dexv, self.intv, self.chrv, self.lckv)
class Warrior(Occupation):
def __init__(self):
super(Warrior, self).__init__('Warrior', 75, 50, 25, 12, 8, 12, 5, 8, 5)
'root.py' file:
from player import Player
import objects
def new_game():
while True:
print 'Only one class, and it is Warrior!'
print objects.Warrior()
classchoice = raw_input('Please type the full name of the class you wish to select.: ').lower()
playerclass = classchoice.title()
if classchoice != '':
characterclass = getattr(objects, playerclass)
player.health = characterclass.health
player.stamina = characterclass.stamina
player.mana = characterclass.mana
player.skills['str'] = characterclass.strv
player.skills['def'] = characterclass.defv
player.skills['dex'] = characterclass.dexv
player.skills['int'] = characterclass.intv
player.skills['chr'] = characterclass.chrv
player.skills['lck'] = characterclass.lckv
print 'You have chosen {0} as your class.'.format(characterclass.name)
confirm = raw_input('Is this correct? Type [Y] or [N] for yes/no respectively.: ').lower()
if confirm == 'y':
break
elif confirm == 'n':
continue
else:
print 'Not a valid keystroke!'
continue
The problem appears when typing 'warrior' when choosing a player class.:
line 48[in my original file]: player.health = characterclass.health
AttributeError: type object 'Warrior' has no attribute 'health'
It seems that I can't reference the variables that I want to, when trying to update pre-existing Player values. The 'Warrior' class, as far as I can tell, has the variable 'health', but I can't seem to access it. Am I misunderstanding how classes and subclasses work in Python? Or is it something else?
Thanks for any help.
I would like to disagree with Charles Merriam's answer. I fancy the different classes. Yes in the beginning they all look alike and just have different stats. But later on you can extend them to hold multiple functionalities. For example special modifiers such as "rage" for Warrior or "meditation" for Wizard.
If you put all your eggs in a single Character class and just represent different classes as a string attribute of Character class, then you won't be able to do this extending later on. In fact I added the rage method to Warrior at the very end when I came to post this and saw Charles Merriam's answer. And those are the only lines I had to change because I used this inheritance model of yours. (Originally I only wanted to show you composition.)
Composition
Before I showcase what this inheritance thing can do back to what I think you're doing wrong. I think You've created a class inheritance model for your Occupations, but then lost your way and wanted to push it all in the Player class as attributes.
To be more hands on: You defined an Occupation class that holds stats (hp, mana, stamina, dexterity ...). Then you created a Player object and made it exactly the same, except for some extra items, victory... attributes. If you've spent all this effort coding stats as attributes of Occupation classes why would you want for the Player to have specific, independent stats as if Occupations don't exist? You wouldn't.
But what to do exactly? I figure an Occupation can't own items. We haven't coded Occupation like that and it's a bit weird for a system of teachings and ideas to own anything anyhow. So I want to avoid having to inherit Occupations with the Player. A Player is not an extension of Occupation even if a Player can have an Occupation. Therefore, what we want is a composition.
That's when you take an Occupation object, and assign it as an attribute to a Player object.
class CharClass(object):
#these stats have to be defined for EVERY occupation possible
#This can be used as a base class for players without defined classes yet
#by defining the default values of __init__
def __init__(self, name="Unknown", health=30, stamina=10, mana=10,
strv=1, defv=1, dexv=1, intv=0, chrv=0, lckv=0):
self.name = name
self.health = health
self.stamina = stamina
self.mana = mana
self.strv = strv #skill values
self.defv = defv
self.dexv = dexv
self.intv = intv
self.chrv = chrv
self.lckv = lckv
def __str__(self):
details = '{0}: HP: {1}, SP: {2}, MP: {3} \n'+\
'[STR: {4}, DEF: {5}, DEX: {6}, INT: {7}, CHR: {8}, LCK: {9}]'
return details.format(self.name, self.health, self.stamina, self.mana, self.strv,
self.defv, self.dexv, self.intv, self.chrv, self.lckv)
class Warrior(CharClass):
def __init__(self):
super(Warrior, self).__init__(health=100, stamina=50, dexv=20)
def __str__(self):
parentstring = super(Warrior, self).__str__()
return "You are a Warrior \n"+parentstring
class Player(object):
def __init__(self, charclass=CharClass(), items=[], spells=[], victory=False):
self.charclass = charclass #the generic class is the default one
self.items = items
self.spells = spells
Now that we used composition, you don't have to set any of the stats for player individually. That makes your code a lot shorter and more readable. You can access those through a Warrior object, which is an attribute of your player class like this:
newplayer = Player()
print newplayer
print newplayer.charclass
print
#graduating to a Warrior
newplayer.charclass = Warrior()
print newplayer
print newplayer.charclass
print
#there's a snag though. Every time now if you want to print or change Players health
#(or some other attribute) you'd have to spell all of this:
print newplayer.charclass.health
newplayer.charclass.health += 100
print newplayer.charclass.health
#this is because Player object contains a Warrior object in it and what you really change is that
#Warrior object and not the Player.
print type(newplayer.charclass)
Output of the above code would be:
<__main__.Player object at 0x000000000427A550>
Unknown: HP: 30, SP: 10, MP: 10
[STR: 1, DEF: 1, DEX: 1, INT: 0, CHR: 0, LCK: 0]
<__main__.Player object at 0x000000000427A550>
You are a Warrior
Unknown: HP: 100, SP: 50, MP: 10
[STR: 1, DEF: 1, DEX: 20, INT: 0, CHR: 0, LCK: 0]
100
200
<class '__main__.Warrior'>
Seamless Composition
There's a trick/workaround around the snag, albeit it's a bit harder for someone new to get it. Don't fret it, look it back up in a month when the world makes more sense.
Special functions __getattr__ and __setattr__ are called whenever the attribute couldn't be found where it was expected. We override those functions to intercept what the special signs . (in i.e. self.attribute) and = do. Instead of those operators setting or getting the attributes of Player class we make them sometimes set/get the attributes of the composited self.charclass object instead!
class Player(object):
def __init__(self, charclass=CharClass(), items=[], spells=[], victory=False):
self.charclass = charclass
self.items = items
self.spells = spells
def __getattr__(self, attr):
return getattr(self.charclass, attr)
def __setattr__(self, attr, val):
if "charclass" in vars(self) and attr in vars(self.charclass):
self.charclass.__dict__[attr] = val
else:
self.__dict__[attr] = val
With this in place we can do this again (without having to write charclass everywhere:
print newplayer.health
newplayer.health -= 50
print newplayer.health
Output is:
200
150
It's hard to work with __getattr__ and __setattr__ without getting errors. They're not easy functions to overwrite.
It's easier with __getattr__, it will automatically get called whenever there's nothing with the same name in the Player object. So all you have to be careful of is not adding new attributes with the same name in Player.
But __setattr__ will also get called in the __init__ function when Player object doesn't have any attributes yet. If we don't check for that, we will get an error. That's what if "charclass" in vars(self) does; checks if __init__ added charclass attribute to our object.
But if we just check for charclass attribute, what happens when we try to add another? i.e. 2nd one in the row: items? __setattr__ would be called, it would check for charclass in self, it would see it is there and then it would add items to self.charclass and not self! In effect it would add attributes to the Warrior object and not Player object.
How do we add a new attribute to a Player object then? Answer is that we only set already existing Warrior object attributes. All attributes that don't exist in Warrior (self.charclass) are set as attributes of the Player instance (self.__dict__[attr] = val). That's what and attr in vars(self.charclass) means.
Inheritance and composition help extending code later on
To jump back to top and to why I disagree with Charles Merriam's answer. To exntend and change the functionality of your code now, all you have to do additionally is to add methods to Warrior class, for example let's add rageOn and rageOff methods:
class Warrior(CharClass):
#this class basically just defines different default values than CharClass
def __init__(self):
super(Warrior, self).__init__(health=100, stamina=50, dexv=20)
def __str__(self):
parentstring = super(Warrior, self).__str__()
return "You are a Warrior \n"+parentstring
def rageON(self):
print "You are in a blood-rage +30 attack modifier"
self.stamina += 30
def rageOFF(self):
print "You have calmed down."
self.stamina -= 30
And they will be immediately available in your Player class without you having to change the Player at all.
newplayer.rageON()
print newplayer.charclass
print "----------------------------------------------------------------------------------------"
newplayer.rageOFF()
print newplayer.charclass
Output:
You are in a blood-rage +30 attack modifier
You are a Warrior
Unknown: HP: 150, SP: 80, MP: 10
[STR: 1, DEF: 1, DEX: 20, INT: 0, CHR: 0, LCK: 0]
----------------------------------------------------------------------------------------
You have calmed down.
You are a Warrior
Unknown: HP: 150, SP: 50, MP: 10
[STR: 1, DEF: 1, DEX: 20, INT: 0, CHR: 0, LCK: 0]
If you did it all in Player, or Character, class as suggested by Charles; you would have to add a method rage to the Player class. In it you would have to check if you're actually "Warrior" or not and could only then execute it.
This doesn't sound like that much work until you realize that for every special effect of every class you want to have, you would have to write such a method. And they would all have to be in a single file where the Player class is defined. That does sound bad after all. I don't know why I wrote all this but it's too much invested now to not post. Sorry.
characterclass = getattr(objects, playerclass)
getattr() returns the value of named attribute of an object other than the object itself.
characterclass is not an instance of Warrior, therefore you cannot refer to attribute health
getattr(object, name[, default])
Return the value of the named attribute of object. name must be a string. If the string is the name of one of the object’s attributes, the result is the value of that attribute. For example, getattr(x, 'foobar') is equivalent to x.foobar. If the named attribute does not exist, default is returned if provided, otherwise AttributeError is raised.
You need to create warrior instance as:
warrior = objects.Warrior()
warrior.health
Object oriented class structures are a bit confusing.
First option, ignore subclasses. The only difference between a 'Warrior' and a 'Wizard' in your example is data. Just have a Character class and set the data as you would initialize other data:
grak = Player()
grak.occupation = Occupation('Warrior', 75, 50, ....)
Alternately, add a helpful constructor to the Occupation class:
#classmethod
def new_warrior(cls):
return Occupation('Warrior', 75, 50, ....)
# and use this way
grak.occupation = Occupation.new_warrior()
Second, create an instance of a subclass when you want one, like self.occupation = Warrior(). To get the initial instance,
you could use a couple different ways to make a factory method. The easiest to understand is a function like this:
def new_occupation(occupation_string):
if occupation == "Warrior":
return Warrior()
if occupation == "Wizard":
return Wizard()
...
Then you can type my_occupation = new_occupation(playerclass) and my_occupation.strength = 3. Drop the getattr() call.
You want to use subclasses when you are designing code where each instance
will have different data, different classes will have different behaviors, and all subclasses promise to fulfill a single contract. For example, your occupation might promise to implement an attack() method. The Wizard does double damage on a full moon, so its attack() method has
different code. When you call myPlayer.occupation.attack(), the correct attack() method is called, meaning the one for subclass that the instance actually belongs to. If you later add an 'Illusionist' class, you won't change the myPlayer.occupation.attack() line.
Keep coding. It gets better.

How do I pass variables around in Python?

I want to make a text-based fighting game, but in order to do so I need to use several functions and pass values around such as damage, weapons, and health.
Please allow this code to be able to pass "weapons" "damage" "p1 n p2" throughout my code. As you can see I have tried using parameters for p1 n p2, but I am a little bit a newbie.
import random
def main():
print("Welcome to fight club!\nYou will be fighting next!\nMake sure you have two people ready to play!")
p1=input("\nEnter player 1's name ")
p2=input("Enter player 2's name ")
print("Time to get your weapons for round one!\n")
round1(p1,p2)
def randomweapons(p1,p2):
weapon=["Stick","Baseball bat","Golf club","Cricket bat","Knife",]
p1weapon=random.choice(weapon)
p2weapon=random.choice(weapon)
print(p1 +" has found a "+p1weapon)
print(p2 +" has found a "+p2weapon)
def randomdamage():
damage=["17","13","10","18","15"]
p1damage=random.choice(damage)
p2damage=random.choice(damage)
def round1(p1,p2):
randomweapons(p1,p2)
def round2():
pass
def round3():
pass
def weaponlocation():
pass
main()
There are a few options.
One is to pass the values as parameters and return values from your various functions. You're already doing this with the names of the two players, which are passed as parameters from main to round1 and from there on to randomweapons. You just need to decide what else needs to be passed around.
When the information needs to flow the other direction (from a called function back to the caller), use return. For instance, you might have randomweapons return the weapons it chose to whatever function calls it (with return p1weapon, p2weapon). You could then save the weapons in the calling function by assigning the function's return value to a variable or multiple variables, using Python's tuple-unpacking syntax: w1, w2 = randomweapons(p1, p2). The calling function could do whatever it wants with those variables from then on (including passing them to other functions).
Another, probably better approach is to use object oriented programming. If your functions are methods defined in some class (e.g. MyGame), you can save various pieces of data as attributes on an instance of the class. The methods get the instance passed in automatically as the first parameter, which is conventionally named self. Here's a somewhat crude example of what that could be like:
class MyGame: # define the class
def play(self): # each method gets an instance passed as "self"
self.p1 = input("Enter player 1's name ") # attributes can be assigned on self
self.p2 = input("Enter player 2's name ")
self.round1()
self.round2()
def random_weapons(self):
weapons = ["Stick", "Baseball bat", "Golf club", "Cricket bat", "Knife"]
self.w1 = random.choice(weapons)
self.w2 = random.choice(weapons)
print(self.p1 + " has found a " + self.w1) # and looked up again in other methods
print(self.p2 + " has found a " + self.w2)
def round1(self):
print("Lets pick weapons for Round 1")
self.random_weapons()
def round2(self):
print("Lets pick weapons for Round 2")
self.random_weapons()
def main():
game = MyGame() # create the instance
game.play() # call the play() method on it, to actually start the game

AtrributeError: type object 'Player' has no attribute 'image_dict'

Been trying to get a dictionary working for some sprites.
class Player(Digimon):
def __init__(self):
super(Player, self).__init__(0,2,0,0,0,0) # age, weight, str, def, speed, intelligence
self.image_dict = {(0,2,0,0,0,0): itertools.cycle([pygame.image.load("images/egg_sprite_1.png"),
pygame.image.load("images/egg_sprite_2.png"),
pygame.image.load("images/egg_sprite_3.png")]),
(2,4,0,0,2,5): itertools.cycle([pygame.image.load("images/leaf_1.png"),
pygame.image.load("images/leaf_2.png"),
pygame.image.load("images/leaf_3.png"),
pygame.image.load("images/leaf_4.png")])}
and then in the main loop
Player.images = Player.image_dict[(Player.age, Player.weight, Player.strength, Player.defence, Player.speed, Player.intelligence)]
Player.image = next(Player.images)
I get the error stated in the title. I've looked at similar questions, but they don't seem to help. As far as I can see, it should work. Player.image_dict is created in the Player(digimon) subclass, so I don't know how there is no attribute.
Well, you actually need to create an instance of the Player class as follows:
player = Player()
Then you can call:
player.images = player.image_dict[(player.age, player.weight, player.strength, player.defence, player.speed, player.intelligence)]
player.image = next(player.images)
Note these are player the object, not Player the class
Player.image_dict
this way you can only access ststic members of class Player. If you dont want to do that you need to create a object of the class player. like this
Player player = Player(<arguments>)
player.image_dict(...)

Creating dynamic variables for a class from within the class

For context, I'm working on an inventory system in an RPG, and I'm prototyping it with python code.
What I don't understand is how to make separate variables for each instance of an item without declaring them manually. For a short example:
class Player(object):
def __init__(self):
self.Items = {}
class Item(object):
def __init__(self):
self.Equipped = 0
class Leather_Pants(Item):
def __init__(self):
#What do i place here?
def Pick_Up(self, owner):
owner.Items[self.???] = self #What do i then put at "???"
def Equip(self):
self.Equipped = 1
PC = Player()
#Below this line is what i want to be able to do
Leather_Pants(NPC) #<-Create a unique instance in an NPC's inventory
Leather_Pants(Treasure_Chest5) #Spawn a unique instance of pants in a treasure chest
Leather_Pants1.Pick_Up(PC) #Place a specific instance of pants into player's inventory
PC.Items[Leather_Pants1].Equip() #Make the PC equip his new leather pants.
If I did something silly in the above code, please point it out.
What I want to do if the code doesn't make it clear is that I want to be able to dynamically create variables for all items as I spawn them, so no two items will share the same variable name which will serve as an identifier for me.
I don't mind if I have to use another class or function for it like "Create_Item(Leather_Pants(), Treasure_Chest3)"
What's the best way to go about this, or if you think I'm doing it all wrong, which way would be more right?
As a general rule, you don't want to create dynamic variables, and you want to keep data out of your variable names.
Instead of trying to create variables named pants0, pants1, etc., why not just create, say, a single list of all leather pants? Then you just do pants[0], pants[1], etc. And none of the other parts of your code have to know anything about how the pants are being stored. So all of your problems vanish.
And meanwhile, you probably don't want creating a Leather_Pants to automatically add itself to the global environment. Just assign it normally.
So:
pants = []
pants.append(Leather_Pants(NPC))
pants.append(Leather_Pants(chests[5]))
pants[1].pickup(PC)
The pants don't have to know that they're #1. Whenever you call a method on them, they've got a self argument that they can use. And the player's items don't need to map some arbitrary name to each item; just store the items directly in a list or set. Like this:
class Player(object):
def __init__(self):
self.Items = set()
class Item(object):
def __init__(self):
self.Equipped = 0
class Leather_Pants(Item):
def __init__(self):
pass # there is nothing to do here
def Pick_Up(self, owner):
self.owner.Items.add(self)
def Equip(self):
self.Equipped = 1
Abernat has tackled a few issues, but I thought I weigh in with a few more.
You appear to be using OOP, but are mixing a few issues with your objects. For example, my pants don't care if they are worn or not, I care though for a whole host of reasons. In python terms the Pants class shouldn't track whether it is equipped (only that it is equippable), the Player class should:
class CarryableItem:
isEquipable = False
class Pants(CarryableItem):
isEquipable = True
class Player:
def __init__(self):
self.pants = None # Its chilly in here
self.shirt = None # Better take a jumper
self.inventory = [] # Find some loot
def equip(self,item):
if is.isEquipable:
pass # Find the right slot and equip it,
# put the previously equipped item in inventory, etc...
Also, its very rare that an item will need to know who its owner is, or that its been grabbed, so verbs like that again should go onto the Player:
class Player:
maxCarry = 10
def take(Item):
if len(inventory) < maxCarry:
inventory.append(item)
Lastly, although we've tried to move most verbs on to actors which actually do things, sometimes this isn't always the case. For example, when instantiating a chest:
import random
class StorageItem:
pass
class Chest(StorageItem):
__init__(self):
self.storage = random.randint(5)
self.loot = self.spawnLoot()
def spawnLoot(self):
for i in range(self.storge):
# Lets make some loot
item = MakeAnItem # Scaled according to type level of dungeon, etc.
loot.append(item)
def remove(item):
self.loot[self.loot.index(item)]=None
Now the question about what to do when a Player wants to plunder a chest?
class Player:
def plunder(storage):
for item in storage.loot:
# do some Ui to ask if player wants it.
if item is not None and self.wantsItem(item) or \
(self.name="Jane" and self.wantsItem(item) and self.doesntWantToPay):
self.take(item)
storage.remove(item)
edit: Answering the comment:
If you are curious about calculating armor class, or the like, that again is a factor of the user, not the item. For example:
class Player:
#property
def clothing(self):
return [self.pants,self.top]
#property
def armorClass(self):
ac = self.defence
for item in self.clothing:
def = item.armorClass
if self.race="orc":
if item.material in ["leather","dragonhide"]:
def *= 1.5 # Orcs get a bonus for wearing gruesome dead things
elif item.material in ["wool","silk"]:
def *= 0.5 # Orcs hate the fineries of humans
ac += def
return ac
pants = Pants(material="leather")
grum = Player(race="orc")
grum.equip(pants)
print grum.armorClass
>>> 17 # For example?

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