init

Author: 刘欣

chain_of_responsibility.py

@@ -0,0 +1,39 @@
+class Handler(object):
+
+    def __init__(self):
+        self.successor = None
+
+    def handle(self, data):
+        res = self._handle(data)
+        if res:
+            return res
+        if self.successor:
+            return self.successor.handle(data)
+
+    def _handle(self, data):
+        raise NotImplementedError
+
+    def link(self, handler):
+        self.successor = handler
+        return handler
+
+
+class DictHandler(Handler):
+    def _handle(self, data):
+        if isinstance(data, dict):
+            print("handled by %s" % self)
+            return True
+
+
+class ListHandler(Handler):
+    def _handle(self, data):
+        if isinstance(data, list):
+            print("handled by %s" % self)
+            return True
+
+
+if __name__ == '__main__':
+    h = DictHandler()
+    h.link(ListHandler()).link(Handler())
+    ret = h.handle([1, 2, 3])
+    ret = h.handle({1: 2})

chaining_method.py

@@ -0,0 +1,22 @@
+class Player(object):
+    def __init__(self, name):
+        self.pos = (0, 0)
+
+    def move(self, pos):
+        self.pos = pos
+        print("move to %s, %s" % self.pos)
+        return self
+
+    def say(self, text):
+        print(text)
+        return self
+
+    def home(self):
+        self.pos = (0, 0)
+        print("I am home")
+        return self
+
+
+if __name__ == '__main__':
+    p = Player('liuxin')
+    p.move((1, 1)).say("haha").move((2, 3)).home().say("go to sleep")

command.py

@@ -0,0 +1,38 @@
+from collections import deque
+
+
+class Document(object):
+    value = ""
+    cmd_stack = deque()
+
+    @classmethod
+    def execute(cls, cmd):
+        cmd.redo()
+        cls.cmd_stack.append(cmd)
+
+    @classmethod
+    def undo(cls):
+        cmd = cls.cmd_stack.pop()
+        cmd.undo()
+
+
+class AddTextCommand(object):
+    def __init__(self, text):
+        self.text = text
+
+    def redo(self):
+        Document.value += self.text
+
+    def undo(self):
+        Document.value = Document.value[:-len(self.text)]
+
+
+if __name__ == '__main__':
+    cmds = [AddTextCommand("liu"), AddTextCommand("xin"), AddTextCommand("heihei")]
+    for cmd in cmds:
+        Document.execute(cmd)
+        print(Document.value)
+
+    for i in range(len(cmds)):
+        Document.undo()
+        print(Document.value)

factory.py

@@ -0,0 +1,21 @@
+class Shape(object):
+    @classmethod
+    def factory(cls, name, *args, **kwargs):
+        types = {c.__name__: c for c in cls.__subclasses__()}
+        shape_class = types[name]
+        return shape_class(*args, **kwargs)
+
+
+class Circle(Shape):
+    pass
+
+
+class Square(Shape):
+    pass
+
+
+if __name__ == '__main__':
+    shapes = ["Circle", "Square", "Square", "Circle"]
+    for i in shapes:
+        s = Shape.factory(i)
+        print(s)

iterator.py

@@ -0,0 +1,12 @@
+def fibonacci(count=100):
+    a, b = 1, 2
+    yield a
+    yield b
+    while count:
+        a, b = b, a + b
+        count -= 1
+        yield b
+
+
+for i in fibonacci():
+    print(i)

mvc.py

@@ -0,0 +1,51 @@
+class Model(object):
+    products = {
+        'milk': {'price': 1.50, 'quantity': 10},
+        'eggs': {'price': 0.20, 'quantity': 100},
+        'cheese': {'price': 2.00, 'quantity': 10}
+    }
+
+    def get(self, name):
+        return self.products.get(name)
+
+
+class View(object):
+    def show_item_list(self, item_list):
+        print('-' * 20)
+        for item in item_list:
+            print("* Name: %s" % item)
+        print('-' * 20)
+
+    def show_item_info(self, name, item_info):
+        print("Name: %s Price: %s Quantity: %s" % (name, item_info['price'], item_info['quantity']))
+        print('-' * 20)
+
+    def show_empty(self, name):
+        print("Name: %s not found" % name)
+        print('-' * 20)
+
+
+class Controller(object):
+    def __init__(self, model, view):
+        self.model = model
+        self.view = view
+
+    def show_items(self):
+        items = self.model.products.keys()
+        self.view.show_item_list(items)
+
+    def show_item_info(self, item):
+        item_info = self.model.get(item)
+        if item_info:
+            self.view.show_item_info(item, item_info)
+        else:
+            self.view.show_empty(item)
+
+
+if __name__ == '__main__':
+    model = Model()
+    view = View()
+    controller = Controller(model, view)
+    controller.show_items()
+    controller.show_item_info('cheese')
+    controller.show_item_info('apple')

observer.py

@@ -0,0 +1,29 @@
+class Observable(object):
+
+    def __init__(self):
+        self._observers = []
+
+    def attach(self, observer):
+        if observer not in self._observers:
+            self._observers.append(observer)
+
+    def detach(self, observer):
+        self._observers.remove(observer)
+
+    def notify(self):
+        for observer in self._observers:
+            observer.update(self)
+
+
+class Observer(object):
+    def update(self, observable):
+        print('updating %s by %s' % (self, observable))
+
+
+if __name__ == '__main__':
+    clock = Observable()
+    user1 = Observer()
+    user2 = Observer()
+    clock.attach(user1)
+    clock.attach(user2)
+    clock.notify()