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| -rw-r--r-- | LectureNotesOnPython.rst | 157 |
1 files changed, 155 insertions, 2 deletions
diff --git a/LectureNotesOnPython.rst b/LectureNotesOnPython.rst index 6abf332..0b0c4f2 100644 --- a/LectureNotesOnPython.rst +++ b/LectureNotesOnPython.rst @@ -1858,7 +1858,18 @@ Positional argument. Keyword argument. 继承(inheritance) `````````````````````````````````````````````````` -继承父类中的属性与方法。 +继承用于从父类（parent）中继承属性与方法，创建一个子类 (child)。 如果 +子类中的方法与父类中的方法同名， 则在子类实例中用子类定义的方法 +(overrride)。 利于代码重用。 缺点是代码不易读懂。 并不是非要代码重用 +不可。 + +类关系图（class diagram）。 两类关系， HAS-A 与 IS-A 。 + +HAS-A 。 长方形中有点。 + +IS-A 。 一手牌是一副牌。 + + .. code:: python @@ -1885,12 +1896,154 @@ Positional argument. Keyword argument. -扑克牌。Card, Deck, Hand(Deck)。 +扑克牌。Card 类, Deck 类, Hand(Deck) 类继承 Deck 类。 Hand 是一手牌， 可以用 Deck 中的拿牌与出牌。 + + +类属性（class attribute）与实例属性(instance attribute)。 + +.. code:: python + + """This module contains a code example related to + + Think Python, 2nd Edition + by Allen Downey + http://thinkpython2.com + + Copyright 2015 Allen Downey + + License: http://creativecommons.org/licenses/by/4.0/ + """ + + + import random + + + class Card: + """Represents a standard playing card. + + Attributes: + suit: integer 0-3 + rank: integer 1-13 + """ + + suit_names = ["Clubs", "Diamonds", "Hearts", "Spades"] + rank_names = [None, "Ace", "2", "3", "4", "5", "6", "7", + "8", "9", "10", "Jack", "Queen", "King"] + + def __init__(self, suit=0, rank=2): + self.suit = suit + self.rank = rank + + def __str__(self): + """Returns a human-readable string representation.""" + return '%s of %s' % (Card.rank_names[self.rank], + Card.suit_names[self.suit]) + + def __eq__(self, other): + """Checks whether self and other have the same rank and suit. + + returns: boolean + """ + return self.suit == other.suit and self.rank == other.rank + + def __lt__(self, other): + """Compares this card to other, first by suit, then rank. + + returns: boolean + """ + t1 = self.suit, self.rank + t2 = other.suit, other.rank + return t1 < t2 + + + class Deck: + """Represents a deck of cards. + + Attributes: + cards: list of Card objects. + """ + + def __init__(self): + """Initializes the Deck with 52 cards. + """ + self.cards = [] + for suit in range(4): + for rank in range(1, 14): + card = Card(suit, rank) + self.cards.append(card) + + def __str__(self): + """Returns a string representation of the deck. + """ + res = [] + for card in self.cards: + res.append(str(card)) + return '\n'.join(res) + + def add_card(self, card): + """Adds a card to the deck. + + card: Card + """ + self.cards.append(card) + + def remove_card(self, card): + """Removes a card from the deck or raises exception if it is not there. + + card: Card + """ + self.cards.remove(card) + + def pop_card(self, i=-1): + """Removes and returns a card from the deck. + + i: index of the card to pop; by default, pops the last card. + """ + return self.cards.pop(i) + + def shuffle(self): + """Shuffles the cards in this deck.""" + random.shuffle(self.cards) + + def sort(self): + """Sorts the cards in ascending order.""" + self.cards.sort() + + def move_cards(self, hand, num): + """Moves the given number of cards from the deck into the Hand. + + hand: destination Hand object + num: integer number of cards to move + """ + for i in range(num): + hand.add_card(self.pop_card()) + + + class Hand(Deck): + """Represents a hand of playing cards.""" + + def __init__(self, label=''): + self.cards = [] + self.label = label + + + if __name__ == '__main__': + deck = Deck() + deck.shuffle() + + hand = Hand() + + deck.move_cards(hand, 5) + hand.sort() + print(hand) + + web 应用程序 ```````````` + 在文本框输入文本 `````````````````````````````````````````````````` |