python核心编程十三章练习

13-2

#!/user/bin/env python# -*- coding:utf-8 class MoneyFmt(object):    '''把函数dollarize转换为一个类，并且包含以下的五个方法'''    def __init__(self, value=0.0, default='-'):        self.value = float(value)        self.default = default    def update(self, newvalue=None):        self.value = newvalue    def __repr__(self):        return repr(self.value)    # 相关说明参考13-3.py    def __str__(self):        try:            fl = str(round(self.value, 2))            if self.value < 0:                fl = str(round(self.value, 2)).split('-')[1]            dec = fl.split('.')[1]            while len(dec) < 2:                dec = dec + '0'            fl2 = fl.split('.')[0] + '.' + dec            fl2 = list(fl2)            lens = len(fl2)            i, j = 6, 0            while lens > i:                fl2.insert(-i-j, ',')                i += 3                j += 1            if self.value < 0:                if self.default is not '-':                    self.default = '<->'                return self.default + '$' + ''.join(fl2)            else:                return '$' + ''.join(fl2)        except (TypeError, ValueError):            return 'Input should be a number'        def __nonzero__(self):            return int(self.value)moneyfmt = MoneyFmt(-121234567.8991)print moneyfmtprint moneyfmt.__repr__print MoneyFmt(-121234567.8991,'o')print bool(MoneyFmt(-121234567.8991))moneyfmt.update(0.5)print moneyfmt

13-3

#!/user/bin/env python# -*- coding:utf-8def dollarize(num):    '''编写一个dollarize()函数，它以一个浮点型值作为输入，返回一个字符串形式的金额'''    try:        fl = str(round(num, 2))  # 先对输入的数值取两位小数，并转换为字符串        # 因为round函数的特性，在0.899时无法保留两位数值，所以取小数部分，判断小数位数，补全两位小数        if num < 0:            fl = str(round(num, 2)).split('-')[1]        dec = fl.split('.')[1]  # 小数部分        while len(dec) < 2:            dec = dec + '0'        fl2 = fl.split('.')[0] + '.' + dec  # 对分离部分进行组合        fl2 = list(fl2)        lens = len(fl2)        i, j = 6, 0  # i表示从倒数第六位开始，三位加一个逗号；j则表示插入逗号的个数        # 根据输入数字的长度，判断是否要加逗号，从倒数第六位开始，三位加一个逗号，因为插入都要影响原来排序，所以要对此进行计数j        while lens > i:            fl2.insert(-i-j, ',')            i += 3            j += 1        # 若输入为负数则在$前面加入负号        if num < 0:            return '-' + '$' + ''.join(fl2)        else:            return '$' + ''.join(fl2)    except (TypeError, ValueError):        return 'Input should be a number'print dollarize(1234567.8901)print dollarize(-121234567.8991)print dollarize(1234567)print dollarize('lit')

13-4

#!/user/bin/env python# -*- coding:utf-8import time, getpass, hashlib, shelveclass UserDatabase(object):    def __init__(self, fn):        self.db = shelve.open(fn)    def __del__(self):        self.db.close()    def recive(self, prompt=None, flag=True):        try:            if flag:                reciver = raw_input(prompt).strip().lower()            else:                reciver = getpass.getpass()        except (KeyboardInterrupt, EOFError):            reciver = 'System quit!'        return reciver    def sigup(self):        while True:            user = self.recive('Sigup: ')            if user in self.db:                print 'Username taken, try another!'                continue            elif not user.isalnum() or ' ' in user:                print 'Invalid username!'                continue            else:                break        psw = self.recive(flag=False)        timeNow = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))        self.db[user] = hashlib.md5(psw).hexdigest(), timeNow        print '>You has already sigup, return to login page.>>>'    def login(self):        while True:            user = self.recive('Login: ')            psw = self.recive(flag=False)            if (user in self.db and                    self.db.get(user)[0] == hashlib.md5(psw).hexdigest()):                break            else:                print 'Password or username is not right, try again.'                continue        timeNow = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))        self.db[user] = hashlib.md5(psw).hexdigest(), timeNow        diffTime = float(time.time() - time.mktime(time.strptime(self.db[user][1],'%Y-%m-%d %H:%M:%S'))) / 3600        if diffTime <= 4:            print 'You already logged in at: ', self.db[user][1]        print '>***Welcome, %s!***' % user    def admin(self):        choice = raw_input('del a user or show all users: ').strip()[0].lower()        if choice == 'd':            user = self.recive('Username: ')            if user in self.db:                del self.db[user]                print 'Remove %s ... Done!' % user            else:                print 'User has no name: %s ' % user        elif choice == 's':            for user in self.db:                print user        else:            print 'Invalid input!'    def updatepsw(self):        user = self.recive('Username: ')        if user in self.db:            psw = self.recive(flag=False)            self.db[user] = psw        else:            print 'Username error!'def start():    # 展示你可以输入的标语    prompt = """    (S)igup    (L)ogin    (A)dmin    (Q)uit    >Enter your choice: """    # 是否要跳出循环    done = False    while not done:        # 是否要跳出选择        chosen = False        while not chosen:            try:                choice = raw_input(prompt).strip()[0].lower()            except (EOFError, KeyboardInterrupt):                choice = 'q'            print '\nYou picked: [%s]' % choice            if choice not in 'slaq':                print '>Invalid option, try again!'            else:                chosen = True        if choice == 'q':            done = True        if choice == 's':            user_database.sigup()        if choice == 'a':            user_database.admin()        if choice == 'l':            user_database.login()if __name__ == '__main__':    user_database = UserDatabase('userpw2.shelve')    start()

13-5

#!/user/bin/env python# -*- coding:utf-8 class Point(object):    def __init__(self, x=0, y=0):        self.x = x        self.y = y    def __str__(self):        return '(%s, %s)' % (self.x, self.y)point = Point()print pointpoint = Point(3, 4)print point

13-6

#!/user/bin/env python# -*- coding:utf-8 import mathclass LineSegment(object):    def __init__(self, x1=0, y1=0, x2=0, y2=0):        self.x1 = x1        self.x2 = x2        self.y1 = y1        self.y2 = y2    def __str__(self):        return '(%s, %s), (%s, %s)' % (self.x1, self.y1, self.x2, self.y2)    __repr__ = __str__    def length(self):        self.leng1 = self.y2 - self.y1        self.leng2 = self.x2 - self.x1        leng = math.sqrt(self.leng1 ** 2 + self.leng2 ** 2)        return round(leng, 2)    def slope(self):        k = self.leng1 / self.leng2        return round(k, 2)line = LineSegment(1, 2, 3, 4)print lineprint line.length()print line.slope()

13-7

#!/user/bin/env python# -*- coding:utf-8 import timefrom datetime import dateclass TimeFmt(object):    today = date.today().timetuple()    # 设定默认值为今天    def __init__(self, year=today[0], mon=today[1], day=today[2], fmt=None):        self.year = year        self.mon = mon        self.day = day        self.fmt = fmt    def update(self, year, mon, day):        self.year = year        self.mon = mon        self.day = day    def display(self):        # 为了显示YY需要对年进行切片处理        year = str(self.year)[-2:]        mon = self.mon        day = self.day        # 假如输入的月份和天为个位，则补充零        if self.mon < 10:            mon = '0' + str(self.mon)        if self.day < 10:            day = '0' + str(self.day)        if self.fmt == 'MDY':            return '%s/%s/%s' % (mon, day, year)        elif self.fmt == 'MDYY':            return '%s/%s/%s' % (mon, day, self.year)        elif self.fmt == 'DMY':            return '%s/%s/%s' % (day, mon, year)        elif self.fmt == 'DMYY':            return '%s/%s/%s' % (day, mon, self.year)        elif self.fmt == 'MODYY':            return '%s %s, %s' % (day, mon, self.year)        else:            return time.ctime()timefmt = TimeFmt(2015, 6, 13, 'DMYY')print timefmt.display()timefmt.update(2011, 10, 2)print timefmt.display()

13-8

#!/user/bin/env python# -*- coding:utf-8class Stack(object):    def __init__(self, stack=[]):        self.stack = stack    def __str__(self):        return '%s' % self.stack    __repr__ = __str__    def push(self, item):        self.stack.append(item)  # add an item to the stack    def pop(self):        self.stack.pop()  # remove an item from the stack    def isempty(self):        # Boolean method        if self.stack == []:            return True        else:            return False    def peek(self):        # returns the item at the top of the stack without popping it off        return self.stack[-1]

13-9

#!/user/bin/env python# -*- coding:utf-8class Queue(object):    def __init__(self, queue=[]):        self.queue = queue    def __str__(self):        return '%s' % self.queue    __repr__ = __str__    def enqueue(self, element):        self.queue.append(element)    def dequeue(self):        return self.queue.pop(0)

13-10

#!/user/bin/env python# -*- coding:utf-8class StacksAndQueues(object):    def __init__(self, arr=[]):        self.arr = arr    def __str__(self):        return '%s' % self.arr    __repr__ = __str__    def shift(self):        '''returns the first element and removes it from the list.'''        return self.arr.pop(0)    def unshift(self, element):        '''"pushes" a new element to the front or head of the list'''        self.arr.insert(0, element)    def push(self, element):        '''adds a new element to the end of a list'''        self.arr.append(element)    def pop(self):        '''returns the last element and removes it from the list'''        return self.arr.pop()

13-11

#!/user/bin/env python# -*- coding:utf-8'''Items go in Carts, and Users can have multiple Carts. Also, multiple   items can go into Carts, including more than one of any single item.'''class User(object):    carts = []    print carts    def buy(self, item):        return Cart(item)class Item:    def __init__(self, item):        self.item = itemclass Cart:    def __init__(self, item):        self.items = []        self.items.append(item)        print self.itemsbanana = Item('banana')apple = Item('apple')orange = Item('orange')mike = User()mike.buy(banana)mike.buy(apple)mike.buy(orange)mike.carts = Cart(banana)print mike

13-12

#!/user/bin/env python# -*- coding:utf-8class Message(object):    '''containing a message string and any additional information,    such as broadcast or single recipient'''    def __init__(self, fr, to, info):        self.fr = fr        self.to = to        self.info = info    def fr(self):        return self.fr    def to(self):        return self.to    def info(self):        return self.infoclass User(object):    '''contains all the information for a persion entering your chat rooms'''    def __init__(self, username, sex):        self.username = username        self.sex = sex    def __str__(self):        return '%s, %s' % (self.username, self.sex)    __repr__ = __str__    def send(self, room, to, info):        message = Message(self.username, to, info)        return room.reciver(message)    def quit_room(self, room):        return room.quit(self.username)    def create_room(self, roomname):        return Room(roomname, self.username)class Room(object):    '''users can create separate 'room' within the chat area and    invite others to join'''    def __init__(self, roomname, creator):        self.roomname = roomname        self.users = []        self.users.append(creator)    def __str__(self):        return '%s: create by %s, members: %s' % \            (self.roomname, self.users[0], ' '.join(self.users))    __repr__ = __str__    def invite(self, user):        self.user = user        self.users.append(user.username)        print '%s has been invited.' % user.username    def reciver(self, message):        if message.fr in self.users:            if message.to in self.users:                print '%s@%s:%s' % (message.fr, message.to, message.info)            elif message.to == 'all':                print '%s@%s:%s' % (message.fr, message.to, message.info)            else:                print '%s is not in this room' % message.to        else:            print 'You are not in this room'    def quit(self, username):        try:            self.users.remove(username)            print '%s has quit.' % username        except ValueError:            print 'You are not in this room'

13-13

#!/user/bin/env python# -*- coding:utf-8import time, jsondb = {300059:[u'东方财富', 'Wes Jul 13 15:15:12 2016', 22.43, 1000]}db_json = json.dumps(db, ensure_ascii=False)class bond(object):    def add(self, code, arr):        db_json[code] = arr    def dele(self, code):        if code in db_json:            print '%s sold out.' % code            del db_json[code]        else:            print 'No such stock code'

13-14

#!/user/bin/env python# -*- coding:utf-8import osimport subprocessclass UnixCmd(object):    def __cd__(self, path):        self.redirect_stdout('cd', path)    def __ls__(self):        self.redirect_stdout('dir', os.getcwd())    def __cat__(self, fname):        self.redirect_stdout('type', fname)    def __cp__(self, fname, path):        self.redirect_stdout('copy', fname, path)    def __mv__(self, org_name, new_name):        self.redirect_stdout('ren', org_name, new_name)    def __rm__(self, fname):        self.redirect_stdout('del', fname)    def __more__(self, fname):        self.redirect_stdout('more', fname)    @staticmethod    def redirect_stdout(cmd, *path):        line = 0        fp = subprocess.Popen([cmd, path], stdout=subprocess.PIPE,                              stderr=subprocess.STDOUT, shell=True)        for eachline in fp.stdout:            line += 1            print eachline.strip('\r\n')            if line >= 32:                raw_input('-more-')def shell():    cmd = UnixCmd()    sh_cmd = {'cd': cmd.__cd__, 'ls': cmd.__ls__, 'cat': cmd.__cat__,              'cp': cmd.__cp__, 'mv': cmd.__mv__, 'rm': cmd.__rm__,              'more': cmd.__more__}    while True:        msg = raw_input('[%s:]$' % os.name).strip()        sh = msg.split(' ')        if sh[0] not in sh_cmd.keys():            print 'Invalid command.'            continue        if msg == 'ls':            sh_cmd[msg]()            continue        # 如果只输入了一个命令，没有path或者filename且不为ls命令，则默认在后面加多一个空位键补充，防止超出列表错误        if len(sh) < 2:            sh.append('')        if sh[0] in ['cd', 'cat', 'rm', 'more']:            sh_cmd[sh[0]](sh[1])            continue        if len[sh] < 3:            sh.append('')        if sh[0] in ['mv', 'cp']:            sh_cmd[sh[0]](sh[1], sh[2])        if sh[0] == 'exit':            breakshell()

13-16

#!/user/bin/env python# -*- coding:utf-8import osclass CapOpen(object):    def __init__(self, fn, mode='r', buf=-1):        self.file = open(fn, mode, buf)    def __str__(self):        return str(self.file)    __repr__ = __str__    def write(self, line):        self.file.write(line.upper())    def writeline(self, lines, newline=False):        for line in lines:            if newline:                line += os.linesep            self.file.write(line.upper())                def __getattr__(self, attr):        return getattr(self.file, attr)

13-17

#!/user/bin/env python# -*- coding:utf-8 class RoundFloat(float):    def __new__(cls, value):        return super(RoundFloat, cls).__new__(cls, round(value, 2))class MoneyFmt(object):    '''把函数dollarize转换为一个类，并且包含以下的五个方法'''    def __init__(self, value=0.0, default='-'):        self.value = float(value)        self.default = default    def update(self, newvalue=None):        self.value = newvalue    def __repr__(self):        return repr(self.value)    # 相关说明参考13-3.py    def __str__(self):        try:            fl = str(RoundFloat(self.value))            if self.value < 0:                fl = str(RoundFloat(self.value)).split('-')[1]            dec = fl.split('.')[1]            while len(dec) < 2:                dec = dec + '0'            fl2 = fl.split('.')[0] + '.' + dec            fl2 = list(fl2)            lens = len(fl2)            i, j = 6, 0            while lens > i:                fl2.insert(-i-j, ',')                i += 3                j += 1            if self.value < 0:                if self.default is not '-':                    self.default = '<->'                return self.default + '$' + ''.join(fl2)            else:                return '$' + ''.join(fl2)        except (TypeError, ValueError):            return 'Input should be a number'        def __nonzero__(self):            return int(self.value)

13-18

#!/user/bin/env python# -*- coding:utf-8import time, getpass, hashlib, shelveclass UserDatabase(object):    def __init__(self, fn):        self.db = shelve.open(fn)    def __del__(self):        self.db.close()    def recive(self, prompt=None, flag=True):        try:            if flag:                reciver = raw_input(prompt).strip().lower()            else:                reciver = getpass.getpass()        except (KeyboardInterrupt, EOFError):            reciver = 'System quit!'        return reciver    def sigup(self):        while True:            user = self.recive('Sigup: ')            if user in self.db:                print 'Username taken, try another!'                continue            elif not user.isalnum() or ' ' in user:                print 'Invalid username!'                continue            else:                break        psw = self.recive(flag=False)        timeNow = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))        self.db[user] = hashlib.md5(psw).hexdigest(), timeNow        print '>You has already sigup, return to login page.>>>'    def login(self):        while True:            user = self.recive('Login: ')            psw = self.recive(flag=False)            if (user in self.db and                    self.db.get(user)[0] == hashlib.md5(psw).hexdigest()):                break            else:                print 'Password or username is not right, try again.'                continue        timeNow = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))        self.db[user] = hashlib.md5(psw).hexdigest(), timeNow        diffTime = float(time.time() - time.mktime(time.strptime(self.db[user][1],'%Y-%m-%d %H:%M:%S'))) / 3600        if diffTime <= 4:            print 'You already logged in at: ', self.db[user][1]        print '>***Welcome, %s!***' % user    def admin(self):        choice = raw_input('del a user or show all users: ').strip()[0].lower()        if choice == 'd':            user = self.recive('Username: ')            if user in self.db:                del self.db[user]                print 'Remove %s ... Done!' % user            else:                print 'User has no name: %s ' % user        elif choice == 's':            for user in self.db:                print user        else:            print 'Invalid input!'    def updatepsw(self):        user = self.recive('Username: ')        if user in self.db:            psw = self.recive(flag=False)            self.db[user] = psw        else:            print 'Username error!'def start():    # 展示你可以输入的标语    prompt = """    (S)igup    (L)ogin    (A)dmin    (Q)uit    >Enter your choice: """    # 是否要跳出循环    done = False    while not done:        # 是否要跳出选择        chosen = False        while not chosen:            try:                choice = raw_input(prompt).strip()[0].lower()            except (EOFError, KeyboardInterrupt):                choice = 'q'            print '\nYou picked: [%s]' % choice            if choice not in 'slaq':                print '>Invalid option, try again!'            else:                chosen = True        if choice == 'q':            done = True        if choice == 's':            user_database.sigup()        if choice == 'a':            user_database.admin()        if choice == 'l':            user_database.login()if __name__ == '__main__':    user_database = UserDatabase('userpw2.shelve')    start()

13-19

class SortedKeyDict(dict):    def key(self):        return sorted(self.keys())d = SortedKeyDict((('zheng-cai', 67), ('hui-jun', 68), ('xin-yi', 2)))print 'By iterator:'.ljust(12), [key for key in d]print 'By keys():'.ljust(12), d.key()

13-20

#!/user/bin/env python# -*- coding:utf-8class Time60(object):    def __init__(self, *val):        if isinstance(val[0], str):            self.hr = int(val[0].split(':')[0])            self.mi = int(val[0].split(':')[1])        elif isinstance(val[0], dict):                self.hr = val[0]['hr']                self.mi = val[0]['min']        elif isinstance(val[0], tuple):            self.hr = val[0][0]            self.mi = val[0][1]        elif isinstance(val[0], int):            self.hr = val[0]            self.mi = val[1]        else:            self.hr = 0            self.mi = 0    def __str__(self):        return '%02d:%02d' % (self.hr, self.mi)    __repr__ = __str__    def __add__(self, other):        return self.__class__(self.hr + other.hr,                              self.mi + other.mi)    def __iadd__(self, other):        self.hr += other.hr        self.mi += other.mi        return self