Python核心编程v2.0 第13章习题（上）

2.
方法是定义在类中的功能函数，只能被实例调用，在所有的方法声明中都必须有self参数。算一种特殊的函数
函数是可以调用的实体，是对程序逻辑进行结构化或过程化的一种编程方法
3.

# -*- coding: utf-8 -*-class MoneyFmt(object):    #这个函数写复杂了，可以参考format（）函数，相当于自己实现了一次format函数    def dollarize(self,index=1):        money = self.money        st = str(money)        li = st.split('.')        count = len(li[0])/3        #先将符号去掉并记录        if li[0][0] == '-':            if index == 1:                re = '-'            else:                re = '<->'            li[0]=li[0][1:]        else:            re = ''         #数字位不满时补足便于添加逗号        if len(li[0])%3 != 0:            li[0]=li[0].rjust((count+1)*3)        newli = []        i = 0        while i < len(li[0])/3:            # print li[0][0 + i * 3:3 + i * 3]            newli.append(li[0][0+i*3:3+i*3])            i=i+1        #插入逗号以及添加符号        st = ','.join(newli).lstrip()        st = re+'$'+st+'.'+li[1]        return st    #在类初始化的时候传入d选项需要的参数便于__str__调用    def __init__(self,money,index):        self.money = money        self.index = index    def update(self,newmoney):        self.money = newmoney    def __nonzero__(self):        if self.money != 0:            return True    def __repr__(self):        return self.money    def __str__(self):        return self.dollarize(self.index)if __name__ =='__main__':    mon = MoneyFmt(-1234567.88,0)    print mon.dollarize()    print mon

4.

# -*- coding: utf-8 -*-import timeclass userdb(object):    db = {}    index = False    #初始化时加载文件信息    def __init__(self):        f = open('ar.txt','r')        lines = f.readlines()        f.close()        for line in lines:            #split返回的是list            st1 = line.split(':')            st2 = st1[1].split(',')            name = st1[0]            paswd = int(st2[0])            time = st2[1].strip()            li = []            li.append(paswd)            li.append(time)            self.db[name] = li    #登录    def login(self,name,paswd):        if self.db[name][0] == paswd:            print 'your last time login:',self.db[name][1]            self.db[name][1] = time.strftime("%Y %m %d %H %M", time.localtime())            self.index = True        else:            print 'login fail'    #添加    def adduser(self,newname,newpaswd):        if self.index == True:            ti = time.strftime("%Y %m %d %H %M", time.localtime())            li = []            li.append(newpaswd)            li.append(ti)            self.db[newname] = li        else:            print 'you have not login in'    def __del__(self):        f = open('ar.txt','w')        for keys in self.db:            st = keys+':'+str(self.db[keys][0])+','+self.db[keys][1]            # print st            f.write(st)            f.write('\n')        f.close()if __name__ =='__main__':    user = userdb()    user.login('Anna',2727)    user.adduser('Cnna',2828)    # for i in user.db:    #     print i,user.db[i]    del user

5.
没啥方法的一个类，只是写了下默认

# -*- coding: utf-8 -*-class point(object):    li = []    def __init__(self,x=0,y=0):        self.li.append((x,y))if __name__ =='__main__':    pi = point(1,19)    print pi.li

6.

# -*- coding: utf-8 -*-from __future__ import divisionimport mathclass point(object):    li = []    def __init__(self,point1,point2):        self.li.append(point1)        self.li.append(point2)    def __str__(self):        ti = (self.li[0],self.li[1])        return str(ti)    __repr__ = __str__    def lenth(self):        q1= abs(self.li[0][0]-self.li[1][0])        q2 = abs(self.li[0][1]-self.li[1][1])        return math.sqrt(q1*q1+q2*q2)    def slope(self):        q1 = abs(self.li[0][0] - self.li[1][0])        q2 = abs(self.li[0][1] - self.li[1][1])        return q2/q1if __name__ =='__main__':    po = point((8,3),(2,5))    print po    print po.lenth()    print po.slope()

7.

# -*- coding: utf-8 -*-import timeclass mytime(object):    def __init__(self,ti = time.localtime()):        self.ti = ti    def update(self,ti = time.localtime()):        self.ti = ti    def display(self,str=''):        if str == 'MDY':            return time.strftime('%m/%d/%y',self.ti)        elif str == 'MDYY':            return time.strftime('%m/%d/%Y',self.ti)        elif str == 'DMY':            return time.strftime('%d/%m/%y',self.ti)        elif str == 'DMYY':            return time.strftime('%d/%m/%Y',self.ti)        elif str == 'MODYY':            return time.strftime('Mon %d,%Y',self.ti)        else:            sec = time.mktime(self.ti)            return time.ctime(sec)if __name__ =='__main__':    # time.strftime("%Y %m %d %H %M", time.localtime())    myti = mytime()    print myti.display('MDY')    print myti.display('DMYY')    print myti.display('MODYY')    myti.update()    print myti.display()

8.

# -*- coding: utf-8 -*-class Stack(object):    def __init__(self):        self.stack = []    def push(self,num):        self.stack.append(num)        print self.stack    def isempty(self):        if len(self.stack) == 0:            return 1        else:            0    def pop(self):        if self.isempty() != 1:            if hasattr(self.stack,'pop'):                print 'has this attr'                self.stack.pop()            else:                newstack = []                i = 0                while i <len(self.stack)-1:                    newstack.append(self.stack[i])                    i = i+1                self.stack = newstack            print self.stack        else:            print 'empty stack can not pop'    def peek(self):        return self.stack[len(self.stack)-1]if __name__ =='__main__':    stack = Stack()    stack.push(8)    stack.push(12)    stack.pop()    print stack.peek()

9.

class queue(object):    def __init__(self):        self.que = []    def enqueue(self,num):        self.que.append(num)        print self.que    def dequeue(self):        #这个地方忘记了要判断队列是否为空了        newqu = []        num = self.que[0]        i = 1        while i<=len(self.que)-1:            newqu.append(self.que[i])            i = i+1        self.que = newqu        print self.que        return numif __name__ =='__main__':    que = queue()    que.enqueue(9)    que.enqueue(10)    print que.dequeue()

10.
在stack基础上改的

# -*- coding: utf-8 -*-class StackandQue(object):    def __init__(self):        self.stack = []    def push(self,num):        self.stack.append(num)        print self.stack    def isempty(self):        if len(self.stack) == 0:            return 1        else:            0    def shirf(self):        if self.isempty() !=1:            newqu = []            num = self.stack[0]            i = 1            while i<=len(self.stack)-1:                newqu.append(self.stack[i])                i = i+1            self.stack = newqu            print self.stack            return num        else:            print 'empty '    def pop(self):        if self.isempty() != 1:            if hasattr(self.stack,'pop'):                print 'has this attr'                self.stack.pop()            else:                newstack = []                i = 0                while i <len(self.stack)-1:                    newstack.append(self.stack[i])                    i = i+1                self.stack = newstack            print self.stack        else:            print 'empty stack can not pop'    def unshif(self,num):        newstack = []        newstack.append(num)        newstack.extend(self.stack)        self.stack = newstack        print self.stackif __name__ =='__main__':    sq = StackandQue()    sq.unshif(8)    sq.unshif(90)    sq.shirf()

11.

# -*- coding: utf-8 -*-#item 维护一个 物品仓库 添加进购物车的操作会调用class Item(object):    #为了每个实例的更改都能被保存，这个地方不能放在初始化里    db = {'apple':4,'pear':1,'chocolate':3}    def check(self,name):        if self.db[name] != 0:            return True        else:            return False    def delete(self,name):        if self.check(name) != 0:            self.db[name] = self.db[name]-1            return True        else:            print name,'already sold out'            return False#car中也有一个字典，用来维护每辆车中的物品class car(object):    def __init__(self,carname):        self.carname = carname        self.car  = {}    def addthing(self,name):        it = Item()        if it.delete(name) == True:            if self.car.has_key(name) == True:                self.car[name] = self.car[name]+1            else:                self.car[name] = 1    def showthings(self):        for i in self.car:            print i,self.car[i]#用户用一个list来存储生成的car对象，之后就用list下标就可以访问到实例class user(object):    def __init__(self):        self.index = 0        self.carlist = []    def addcar(self,carname):        ca = car(carname)        self.carlist.append(ca)    def showcar(self):        for i in self.carlist:            print i.carname    def addthing(self,name,carname):        for i in self.carlist:            if i.carname == carname:                i.addthing(name)    def showthing(self):        for i in self.carlist:            print i.carname,'has things:'            i.showthings()#调用的逻辑 我做的是用户调用车，车在添加物品是调用物体库if __name__ =='__main__':    us = user()    us.addcar('car1')    us.addcar('car2')    us.addthing('pear', 'car1')    us.addthing('pear', 'car2')    # us.addthing('chocolate', 'car1')    us.addthing('pear', 'car2')    us.showthing()

12.
用户可以发送，接收消息，也可以新建房间，在房间中接收发送消息。
写Room的时候设计的不是很对，其实应该统一用message来进行消息的传递才达到了封装的效果。这个地方单独给room一个数据结构来保存消息了，应该在message里面加字段来实现的。
功能很不完善，大概只做到一个信箱的那种感觉。

# -*- coding: utf-8 -*-class message(object):    melib = []    #新生成一条消息,index = 0表示该消息未读    def makenew(self,me,nameto,namefrom):        index = 0        me1 = me+'   from   '+namefrom        li = [me1,nameto,index]        self.melib.append(li)    #为某个用户查询他接收到的消息    def checkmessge(self,name):        for i in self.melib:            if i[1] == name and i[2] == 0:                print i[0]                i[2] = 1class Room(object):    #保存参加该房间的用户名称    namelist = []    #room message对所有成员可见    roommessage = []    def __init__(self,roomname,name1,name2):        self.roomname = roomname        self.namelist.append(name1)        self.namelist.append(name2)    def addmessage(self,me,name):        me1 = me + '  from  '+name        index = 0        li = [me1,index]        self.roommessage.append(li)    def showmessage(self):        for i in self.roommessage:            if i[1] == 0:                print i[0]                i[1] = 1class user(object):    user = []    roomlist = []    #用户属性 暂只设置了姓名    def __init__(self,name):        self.name = name        self.user.append(name)    #用户可以发送信息    def sendmessage(self,userto):        if userto in self.user:            me = raw_input('message:')            mes = message()            mes.makenew(me,userto,self.name)        else:            print 'no such user'    #用户可以接收信息    def accepymessage(self):        mes = message()        mes.checkmessge(self.name)    #创建房间    def makeroom(self,usname,roomname):        ro = Room(roomname,usname,self.name)        self.roomlist.append(ro)    #向房间中发信息    def talkroom(self,roomname,mes):        for i in self.roomlist:            if i.roomname == roomname:                i.addmessage(mes,self.name)    #接收房间中的信息    def showroommessage(self,roomname):        for i in self.roomlist:            if i.roomname == roomname:                i.showmessage()if __name__ == '__main__':    u1 = user('A')    u2 = user('B')    u3 = user('C')    u1.makeroom('B','room1')    u1.talkroom('room1','hello B')    u1.makeroom('C','room2')    u1.talkroom('room2','hello C')    u2.showroommessage('room1')    u3.showroommessage('room2')    u2.talkroom('room1','this is B')    u1.showroommessage('room1')    u1.showroommessage('room2')