106 lines
2.4 KiB
Python
106 lines
2.4 KiB
Python
"""
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实例：
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汤宝宝有一张TODO表，记录着自己想干的事情。
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"""
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from abc import ABC, abstractmethod
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# 任务结构体 - 迭代器元素
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class Todo:
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content: str
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done: bool
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def __init__(self, content: str, done: bool = False):
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self.content = content
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self.done = done
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# 集合接口
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class Collection(ABC):
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@abstractmethod
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def CreateIterator(self) -> "Iterator":
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pass
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# 具体集合 - 汤宝宝的TODO表
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class TodoList(Collection):
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todos: list[Todo]
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def __init__(self, todos: list[Todo]):
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self.todos = todos
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def CreateIterator(self) -> "Iterator":
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return TodoListIterator(self)
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# 迭代器接口
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class Iterator(ABC):
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@abstractmethod
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def First(self) -> Todo:
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pass
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@abstractmethod
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def Next(self) -> Todo | None:
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pass
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@abstractmethod
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def isDone(self) -> bool:
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pass
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@abstractmethod
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def CurrentItem(self) -> int:
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pass
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# 具体迭代器 - 汤宝宝的TODO表迭代器
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class TodoListIterator(Iterator):
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def __init__(self, todo_list: "TodoList"):
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self._todo_list = todo_list
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self._current = 0
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def First(self) -> Todo:
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self._current = 0
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return self._todo_list.todos[self._current]
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def Next(self) -> Todo | None:
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self._current += 1
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if not self.isDone():
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return self._todo_list.todos[self._current]
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return None
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def isDone(self) -> bool:
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return self._current >= len(self._todo_list.todos)
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def CurrentItem(self) -> int:
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if self.isDone():
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return len(self._todo_list.todos)
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return self._current + 1
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if __name__ == "__main__":
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print("============= 迭代器模式 =============")
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# 创建TODO表并添加任务
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todo_list = TodoList(
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todos=[
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Todo("学习Go语言", True),
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Todo("完成设计模式作业", False),
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Todo("锻炼身体", False),
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]
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)
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# 创建迭代器
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iterator = todo_list.CreateIterator()
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# 使用迭代器遍历TODO表
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item = iterator.First()
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while not iterator.isDone():
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done = "已完成" if item and item.done else "未完成"
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print(
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f"当前第 {iterator.CurrentItem()} 项任务内容: {item.content if item else ''} 是否完成: {done}"
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)
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item = iterator.Next()
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print("\n=========== 迭代器模式结束 ===========")
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