Printing nested lists - Python

Question

Can someone help me get this print properly?

class Deck(object):
    def __init__(self):
        self.cards = []
        from random import shuffle
        shuffle(self.cards)

    #views all cards in the deck
    def view_deck(self):
        for x in self.cards:
            print(x.name)

    #takes in an (x) integer and views the top x cards of the deck
    def view_number_of_cards(self, cards_to_view):
        for x in self.cards[:cards_to_view]:
            print(x.name)

class Player(object):
    def __init__(self):
        self.hand = []
        self.row_1 = []
        self.row_2 = []
        self.row_3 = []
        self.row_4 = []
        self.row_5 = []
        self.rows = []
        self.rows.append(self.row_1)
        self.rows.append(self.row_2)
        self.rows.append(self.row_3)
        self.rows.append(self.row_4)
        self.rows.append(self.row_5)
        self.graveyard = []
        self.deck = Deck()

    #draw a card from deck to hand
    def draw_card(self):
        c = self.deck.cards
        cardDrawn = c.pop(0)
        self.hand.append(cardDrawn)

    #shuffle deck
    def shuffle_deck(self):
        from random import shuffle
        shuffle(self.deck.cards)

    def play_card(self, card, row):
        self.rows[row-1].append(card)
        self.graveyard.append(card)
        self.hand.remove(card)

    def update(self):
        i = 1
        for x in self.rows:
            print "Lane "+str(i)+": "+str(x[0]),
            i = i+1

When I try this:

x = Player()
x.deck.cards = [1, 2, 3, 4]
x.draw_card()
x.play_card(x.hand[0], 1)
x.rows
[[1], [], [], [], []]
x.update()

This happens

Lane 1: 1

Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    x.update()
  File "C:/Users/Carl/Desktop/try.py", line 53, in update
    print "Lane "+str(i)+": "+str(x[0]),
IndexError: list index out of range

In the console it seems to be working properly if I try to print "Lane 1: "+rows[0][0] etc but for some reason I keep getting this IndexError which doesn't make sense to me because there are definitely other lists in the x-list range. at worst, because the lists are predefined (row_2 = []) then it should print "Lane 2: " but that doesn't even happen. Thanks for the help!

khagler · Accepted Answer · 2012-12-08 04:45:38Z

2

The problem is that, as you say, row_2 = []. Since it's empty, it has no element at index 0.

To get blank "Lane x:" lines you could rewrite update like so:

def update(self):
    for x in self.rows:
        for i in range(5):
            print("Lane {}: ".format(i), end='')
            if len(x):
                print(x[0])
            else:
                print()

You'll also need to add an import at the beginning of the file to get the print function instead of the print statement:

from __future__ import print_function

edited Dec 8, 2012 at 4:45

answered Dec 8, 2012 at 4:17

khagler

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1 Comment

Carl Reyes Over a year ago

Thanks that makes sense. For some reason I thought it would just print blank. something like "Lane 2: " any idea on how to do that?

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