[Tutor] getting nasty TypeError:
Nathaniel Trujillo
hothottrott at gmail.com
Sun Nov 6 03:02:12 CET 2011
Hello. I am currently working with Python version 3.1.1 . I am working out
of the book called Python Programming for the Absolute Beginner Third
Edition which teaches version 3.1.1 . I wrote the following blackjack
program that is on page 275 and I imported the modules that you see below.
First the cards module which is on page 271 and then the games module which
is on page 268. I tried typing everything in exactly the way it is in the
book but when I run the blackjack program that you see below it will first
ask me how many players just like it should, then I tell it how many
players, then it will ask me the names of each player just like it should,
then I tell it the name of each player and after I do that and press enter
I get the following error message.
Traceback (most recent call last):
File "C:\Python31\blackjack.py", line 184, in <module>
main()
File "C:\Python31\blackjack.py", line 181, in main
game.play()
File "C:\Python31\blackjack.py", line 132, in play
print(player)
File "C:\Python31\blackjack.py", line 34, in __str__
rep = self.name + "\t" + super(BJ_Hand, self).__str__()
TypeError: can only concatenate list (not "str") to list
Here is the blackjack program. It is called blackjack.py
# Blackjack
# From 1 to 7 players compete against a dealer
import cards, games
class BJ_Card(cards.Card):
""" A Blackjack Card. """
ACE_VALUE = 1
@property
def value(self):
if self.is_face_up:
v = BJ_Card.RANKS.index(self.rank) + 1
if v > 10:
v = 10
else:
v = None
return v
class BJ_Deck(cards.Deck):
""" A Blackjack Deck. """
def populate(self):
for suit in BJ_Card.SUITS:
for rank in BJ_Card.RANKS:
self.cards.append(BJ_Card(rank, suit))
class BJ_Hand(cards.Hand):
""" A Blackjack Hand. """
def __init__(self, name):
super(BJ_Hand, self).__init__()
self.name = name
def __str__(self):
rep = self.name + "\t" + super(BJ_Hand, self).__str__()
if self.total:
rep += "(" + str(self.total) + ")"
return rep
@property
def total(self):
# if a card in the hand has value of None, then total is None
for card in self.cards:
if not card.value:
return None
# add up card values, treat each Ace as 1
t = 0
for card in self.cards:
t += card.value
# determine if hand contains an Ace
contains_ace = False
for card in self.cards:
if card.value == BJ_Card.ACE_VALUE:
contains_ace = True
# if hand contains Ace and total is low enough, treat Ace as 11
if contains_ace and t <= 11:
# add only 10 since we've already added 1 for the Ace
t += 10
return t
def is_busted(self):
return self.total > 21
class BJ_Player(BJ_Hand):
""" A Blackjack Player. """
def is_hitting(self):
response = games.ask_yes_no("\n" + self.name + ", do you want a
hit? (Y/N): ")
return response == "y"
def bust(self):
print(self.name, "busts.")
self.lose()
def lose(self):
print(self.name, "loses.")
def win(self):
print(self.name, "wins.")
def push(self):
print(self.name, "pushes.")
class BJ_Dealer(BJ_Hand):
""" A Blackjack Dealer. """
def is_hitting(self):
return self.total < 17
def bust(self):
print(self.name, "busts.")
def flip_first_card(self):
first_card = self.cards[0]
first_card.flip()
class BJ_Game(object):
""" A Blackjack Game. """
def __init__(self, names):
self.players = []
for name in names:
player = BJ_Player(name)
self.players.append(player)
self.dealer = BJ_Dealer("Dealer")
self.deck = BJ_Deck()
self.deck.populate()
self.deck.shuffle()
@property
def still_playing(self):
sp = []
for player in self.players:
if not player.is_busted():
sp.append(player)
return sp
def __additional_cards(self, player):
while not player.is_busted() and player.is_hitting():
self.deck.deal([player])
print(player)
if player.is_busted():
player.bust()
def play(self):
# deal initial 2 cards to everyone
self.deck.deal(self.players + [self.dealer], per_hand = 2)
self.dealer.flip_first_card() # hide dealer's first card
for player in self.players:
print(player)
print(self.dealer)
# deal additional cards to players
for player in self.players:
self.__additional_cards(player)
self.dealer.flip_first_card() # reveal dealer's first
if not self.still_playing:
# since all players have busted, just show the dealer's hand
print(self.dealer)
else:
# deal additional cards to dealer
print(self.dealer)
self.__additional_cards(self.dealer)
if self.dealer.is_busted():
# everyone still playing wins
for player in self.still_playing:
player.win()
else:
# compare each player still playing to dealer
for player in self.still_playing:
if player.total > self.dealer.total:
player.win()
elif player.total < self.dealer.total:
player.lose()
else:
player.push()
# remove everyone's cards
for player in self.players:
player.clear()
self.dealer.clear()
def main():
print("\t\tWelcome to Blackjack!\n")
names = []
number = games.ask_number("How many players? (1 - 7): ", low = 1, high
= 8)
for i in range(number):
name = input("Enter player name: ")
names.append(names)
print()
game = BJ_Game(names)
again = None
while again != "n":
game.play()
again = games.ask_yes_no("\nDo you want to play again?: ")
main()
input("\n\nPress the enter key to exit.")
Here is the cards module I imported. It is called cards.py
# Cards Module
# Basic classes for a game with playing cards
class Card(object):
""" A playing card. """
RANKS = ["A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q",
"K"]
SUITS = ["c", "d", "h", "s"]
def __init__(self, rank, suit, face_up = True):
self.rank = rank
self.suit = suit
self.is_face_up = face_up
def __str__(self):
if self.is_face_up:
rep = self.rank + self.suit
else:
rep = "XX"
return rep
def flip(self):
self.is_face_up = not self.is_face_up
class Hand(object):
""" A hand of playing cards. """
def __init__(self):
self.cards = []
def __str__(self):
if self.cards:
rep = ""
for card in self.cards:
rep += str(card) + "\t"
else:
rep = "<empty>"
return rep
def clear(self):
self.cards = []
def add(self, card):
self.cards.append(card)
def give(self, card, other_hand):
self.cards.remove(card)
other_hand.add(card)
class Deck(Hand):
""" A deck of playing cards. """
def populate(self):
for suit in Card.SUITS:
for rank in Card.RANKS:
self.add(Card(rank, suit))
def shuffle(self):
import random
random.shuffle(self.cards)
def deal(self, hands, per_hand = 1):
for rounds in range(per_hand):
for hand in hands:
if self.cards:
top_card = self.cards[0]
self.give(top_card, hand)
else:
print("Can't continue deal. Out of cards!")
if __name__ == "__main__":
print("This is a module with classes for playing cards.")
input("\n\nPress the enter key to exit.")
And finally, here is the games module I imported. It is called games.py
# Games
# Demonstrates module creation
class Player(object):
""" A player for a game. """
def __init__(self, name, score = 0):
self.name = name
self.score = score
def __str__(self):
rep = self.name + ":\t" + str(self.score)
return rep
def ask_yes_no(question):
"""Ask a yes or no question."""
response = None
while response not in ("y", "n"):
response = input(question).lower()
return response
def ask_number(question, low, high):
"""Ask for a number within a range."""
response = None
while response not in range(low, high):
response = int(input(question))
return response
if __name__ == "__main__":
print("You ran this module directly (and did not 'import' it).")
input("\n\nPress the enter key to exit.")
Can you please tell me what I did wrong? Your help is greatly appreciated.
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