Python和数据结构学习 --- 0

好早前就想开始写了,可以一直懒没写.

书参考的是<Data Structures and Algorithms Using Python>基本是照着来.估计也会把里面的题目做做.

看完后打算看稍微难些的<Python Algorithms - Mastering Basic Algorithms in the Python Language>.

基本是自己的学习笔记.记录下而已.

扯了这么多蛋.开始.

首先第一个基本的结构是一维Array(后面还有多维的).它是个静态数组.可以迭代,获取设置值.

实现如下:

import ctypes

class Array:

    def __init__(self,size):

        assert size > 0,"Array size must be >0"

        self._size = size

        PyArrayType = ctypes.py_object * size

        self._elements = PyArrayType()

        self.clear(None)

    

    def __len__(self):

        return self._size

        

    def clear(self,value):

        for i in range(len(self)):

            self._elements[i] = value

            

    def __getitem__(self,index):

        assert index >= 0 and index < len(self),"Array subsctipt out of range"

        return self._elements[index]

    

    def __setitem__(self,index,value):

        assert index >= 0 and index < len(self),"Array subsctipt out of range"

        self._elements[index] = value

         

    

    def __iter__(self):

        return _ArrayIterator(self._elements)

    

class _ArrayIterator:

    def __init__(self,theArray):

        self._arrayRef = theArray

        self._curNdx = 0

    def __iter__(self):

        return self

    #注意这里提供的是next 而书中提供的是__next__它是对应这3版本中的

    def next(self):

        if self._curNdx < len(self._arrayRef):

            entry = self._arrayRef[self._curNdx]

            self._curNdx += 1

            return entry

        else:

            raise StopIteration

测试也很简单.

发现IPython超好,测试修改啥的都可以在一起.

当然了像Array这个数据结构可以直接使用list实现有2中方法,一是直接继承UserList,或者讲list作为内部元素.这里使用的第二中.

class Array:

    def __init__(self,size):

        self._size = size

        self._elements = [None]*size

        

    def __len__(self):

        return self._size

    

    def clear(self,value):

        for i in range(len(self)):

            self._elements[i] = value

    

    def __getitem__(self,index):

        return self._elements[index]

    

    def __setitem__(self,index,value):

        self._elements[index] = value

            

    def __iter__(self):

        return iter(self._elements)

好好了.明天搞二维的,睡觉先..