Python学习系列(五)

本节主要学习Python 3.1的复杂数据类型，内存管理和模块，下面做了一个Sample:

'''
Created on 2010-4-5

@author: Jamson Huang
'''
import os
#import filecmp
import copy
#Python常用的module: os
#pdb=>调试器
#logging=>记录器
#profile,hotshot,cProfile:性能调试器
#所有类的基类都是Object
if __name__ == '__main__':
    #global zone    
    tempStr = 'start to learn python class'
    intA = 5
    intB = 6
    #type():the type of all objects is 'type'   
    def typeFunc():
        print(type('42'))
        print(type(type('42')))
        print()
    typeFunc()
    #NoneType/None(Python 3.1)<=>Null(Python 2.6)
    def noneFunc():
        print(type(None))
        if (None):
            print('None is False')
        else:
            print('None is not True')
        a = 'adajkd'
    #两个对象之间的比较        
        if (a is None):
            print('a is None')
        else:
            print('a is not None')
        
    noneFunc()
    def moduleFunc():
        print(os.name)
    moduleFunc()
    #CALL self-definiton class
#    policy = Policy() 
#    policy.setPolicyId('1111111')
#    print(policy.getPolicyId())   
    #Python的内存管理：同java语言，程序员本身不需要关心它。由于python采用引用计数的方式，所以垃圾收集器
    #会回收那些计数器为0的变量和类，当然，也可以用del来直接做回收处理。其实，这点同java类似。  
    #Seqence[start1:end1,start2:ed2,...]
    def seqFunc():
        print(tempStr[::-1]) 
        print(tempStr[::-2])
    seqFunc()
    #内建函数:cmp(obj1,obj2)/str(obj)/repr(obj),'obj'/type()/isinstance()
#    print(cmp(str(intA), str(intB))) 
    #工厂函数:file()/dict()/bool()/tuple()/basestring()/unicode()
    print(str(tempStr))
    #id():变量和实例在内存中的标识符
    #存储模型：1.标量/原子类型（数值，字符串）2.容器模型（列表，元组，字典）    
    #更新模型: 1.变量类型：列表,字典；2.不可变类型：数值，字符串，元组
    #访问模型: 1.直接访问：数字； 2.顺序访问:字符串，列表，元组；3.映射访问:字典    
    def complexTypeFunc():
        print(id(tempStr))    
        aList = ['china', 'shanghai']
        print(id(aList))
        aList.append('Python')
        print(aList)
        print(id(aList))
        #列表/元组类型:列表是可变类型，而元组是不可变类型
        aList.append(['3333','4444'])
        print(aList)
        print(aList[3])
        aTuple = ('china','shanghai',['aaaa','bbbb'])
        print(aTuple)
        print(id(aTuple))
        print(aTuple.index('shanghai'))
        print(aTuple[::1])
        print(aTuple[:1])
        print(aTuple[1])
        #copy和deepCopy:deepCopy会完全Create一个新的容器类型。        
        newTuple = copy.copy(aTuple)
        print('Copy:', newTuple)
        print(id(newTuple))
        newDeepTuple = copy.deepcopy(aTuple)
        print('deepCopy:', newDeepTuple)
        print(id(newDeepTuple))
    complexTypeFunc()     

run Python, Console输出如下：

<class 'str'>
<class 'type'>

<class 'NoneType'>
None is not True
a is not None
nt
ssalc nohtyp nrael ot trats
sacnhy re ttas
start to learn python class
11610784
12877952
['china', 'shanghai', 'Python']
12877952
['china', 'shanghai', 'Python', ['3333', '4444']]
['3333', '4444']
('china', 'shanghai', ['aaaa', 'bbbb'])
12868104
1
('china', 'shanghai', ['aaaa', 'bbbb'])
('china',)
shanghai
Copy: ('china', 'shanghai', ['aaaa', 'bbbb'])
12868104
deepCopy: ('china', 'shanghai', ['aaaa', 'bbbb'])
12878432