python基础篇 day2
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1.list 列表
#增加 append insert name = [‘0alex‘,‘1jack‘,‘2snow‘,‘3pig‘] print(name) name.append(‘4snake‘) #追加到末尾 print(name) name.insert(1,‘xxxx‘) #插入到下标为1的位置 name.insert(3,‘qqqq‘) print(name)
#更改下标对应元素
#打印下标对应元素
#循环打印list元素
name1 = [‘0alex‘,‘1jack‘,‘2snow‘,‘3pig‘]
name1[2] = ‘update‘
print(name1)
print(name1[0])
print(name1[3])
print(name1[-1]) #倒数第一个 打印
print(name1[-2]) #倒数第2个 打印
for i in name1: #循环打印list元素
print(i)
#正向切片 name2 = [‘0alex‘,‘1jack‘,‘2snow‘,‘3pig‘,‘4dog‘] print(name2) print(name2[0:3]) #切片[0,3) print(name2[:3]) #切片[0,3) print(name2[0:-1]) #切片[0,-1) 除了倒数第一个都打印 #反向切片 name3 = [‘0alex‘,‘1jack‘,‘2snow‘,‘3pig‘,‘4dog‘] print(name3) print(name3[-1:-3]) #打印为空[] -1是最后一个 print(name3[-3:-1]) #[-3,-1) #步长切片 print(name2[0:-1:2]) #[‘0alex‘, ‘1jack‘, ‘2snow‘, ‘3pig‘] #[‘0alex‘, ‘2snow‘]
#索引（获取下标） 和统计 name4 = [‘0alex‘,‘1jack‘,‘2snow‘,‘3pig‘,‘4dog‘,‘4dog‘] print(name4) print(name4.index(‘1jack‘)) #获取元素对应的下标 print(name4[name4.index(‘1jack‘)]) #获取元素对应的下标,下标对应的元素 print(name4.count(‘4dog‘)) #统计几个4dog
#删除 name4.remove(‘4dog‘) #删除 print(name4) del name4[1] #删除下标1的 print(name4) name4.pop(2) #删除下标2的 name4.pop() #删除,默认下标-1的 print(name4)
#翻转 排序 name5 = [‘0alex‘,‘1jack‘,‘2snow‘,‘3pig‘,‘4dog‘] name5.reverse() #翻转 print(name5) name5.sort() #排序 print(name5)
#扩展 age = [‘22‘,‘33‘,‘44‘] job = [‘it‘,‘teacher‘,‘student‘] age.extend(job) #[‘22‘, ‘33‘, ‘44‘, ‘it‘, ‘teacher‘, ‘student‘] print(age) print(job)
2. 深copy 浅copy
#浅copy name = [‘0alex‘,‘1jack‘,[‘21root‘,‘22redhat‘],‘3snake‘] print(‘name>‘,name) name2 = name.copy() name[3] = ‘吖吖‘ print(‘name>‘,name) print(‘name2>‘,name2) name[2][0] = ‘答复‘ print(‘name>‘,name) print(‘name2>‘,name2)
#浅copy 和浅copy的区别 import copy name3 = [‘0alex‘,‘1jack‘,[‘21root‘,‘22redhat‘],‘3snake‘] name4 = copy.copy(name3) #name4只是复制了name3，name3改变，它也改变 name5 = copy.deepcopy(name3) #name5 重新开辟一块内存地址，指针，name3改变，name5不改变 name3[2][0] = ‘答复‘ print(‘name4>‘,name4) print(‘name5>‘,name5)
#3种浅copy import copy person = [‘0jack‘,[‘10alex‘,‘11root‘]] person2 = copy.copy(person) person3 = person[:] person4 = list(person) print(person2,person3,person4)
2. 元组
#元组， 不可以修改 ‘‘‘ name = (‘jack‘,‘alex‘) name.append(‘root‘) AttributeError: ‘tuple‘ object has no attribute ‘append‘ ‘‘‘ name = (‘jack‘,‘alex‘) print(name.count(‘alex‘)) print(name.index(‘jack‘))
#联合账户，共同存款 salary = 1000 count = [‘name‘,[‘saving‘,salary]] print(count) alex = count[:] wife = count[:] alex[0]=‘alex‘ wife[0]=‘wife‘ count[1][1]= salary+1000 print(alex) print(wife)
3.购物车程序
‘‘‘
程序练习
请闭眼写出以下程序。
程序：购物车程序
需求:
1. 启动程序后，让用户输入工资，然后打印商品列表
2. 允许用户根据商品编号购买商品
3. 用户选择商品后，检测余额是否够，够就直接扣款，不够就提醒
4. 可随时退出，退出时，打印已购买商品和余额
‘‘‘
1 info = ‘‘‘ 2 ---------------- 3 4 Welcome to CBBC 5 6 ---------------- 7 ‘‘‘ 8 print(info) 9 10 11 salary = int(input(‘your salary > ‘).strip()) 12 shopping_list = [] 13 while True: 14 goods_list = [[‘air‘,‘10000‘],[‘apple‘,‘8888‘],[‘mi‘,‘3999‘],[‘coffee‘,‘23‘],[‘page‘,‘1‘]] 15 print(len(goods_list)) 16 for index,item in enumerate(goods_list): 17 print(index,item ) 18 19 20 choice = input(‘your choice [q:exit]> ‘).strip() 21 if choice.isnumeric() and 0 < int(choice) < len(goods_list): 22 choice = int(choice) 23 24 25 if int(goods_list[choice][1]) < salary : 26 salary -= int(goods_list[choice][1]) 27 shopping_list.append(goods_list[choice][0]) 28 print(salary) 29 print(shopping_list) 30 else: 31 print(‘余额不足‘) 32 33 elif choice == ‘q‘: 34 break 35 else: 36 print(‘请重新输入‘) 37 38 39 info_bye = ‘‘‘ 40 --------------- 41 bye - bye 42 --------------- 43 your salary:%s 44 your goods:%s 45 ‘‘‘%(salary,shopping_list) 46 47 print(info_bye)
#打印list的#下标，索引 #下标和索引
goods_list = [[‘air‘,‘10000‘],[‘apple‘,‘8888‘],[‘mi‘,‘3999‘],[‘coffee‘,‘23‘],[‘page‘,‘1‘]]
#下标，索引
for index,item in enumerate(goods_list):
print(index,item)
#索引
for i in goods_list:
print(i)
#下标
for i in goods_list:
print(goods_list.index(i))
#判断是不是数字？？？
choice = input(‘>‘)
if choice.isdigit():
print(‘ok‘)
elif choice.isnumeric():
print(‘11‘)
#高亮显示 print(‘this is a book‘) print(‘this is a \033[32;1m book \033[0m‘)
4.字符串str
name = ‘my name is \t alex‘ print(name.capitalize()) #My name is alex print(name.count(‘a‘)) #2 print(name.center(50,‘+‘)) #++++++++++++++++my name is alex+++++++++++++++++ print(name.endswith(‘ex‘)) #以ex结尾i 返回True print(name.expandtabs(30)) #\t 转换成空格 print(name.find(‘name‘)) #3 print(name[name.find(‘name‘):9]) #切片 name[3:9）
#拼接
name2 = ‘my name is {name},age is {age}‘
print(name2.format(name=‘alex‘,age=‘22‘))
print(name2.format_map({‘name‘:‘jack‘,‘age‘:33}))
#判断是否是什么 print(name.isalnum()) #阿拉伯数字 print(‘123aa‘.isalnum()) print(‘adfaDFAS‘.isalpha()) print(‘233‘.isdecimal()) print(‘-44‘.isdigit()) #是否整数 print(‘ 9 44‘.isnumeric()) #是否只有数字 print(‘asf##‘.isdecimal()) print(‘My‘.istitle()) print(‘My‘.isprintable()) print(‘My‘.isupper())
#拼接 print(‘My name is ‘.join(‘==/+‘)) # = = / + print(‘+‘.join([‘1‘,‘3‘,‘4‘])) #1+3+4 print(‘aaaa‘.ljust(50,‘+‘)) print(‘aaaa‘.rjust(50,‘+‘)) print(‘aleEXSSnn‘.zfill(20)) #00000000000aleEXSSnn
#大小写 print(‘SNAEKwe‘.lower()) #snaekwe print(‘SNAEKwe‘.upper()) #SNAEKWE print(‘aleEXSSnn‘.swapcase()) #ALEexssNN
#去除空格，换行 print(‘\talex\t‘.lstrip()) print(‘\talex\t‘.rstrip()) #alex # alex print(‘ \nalex\t‘.strip()) #alex
#替换 password = str.maketrans(‘abcde123‘,‘12345kdf‘) #abcde123 #12345kdf #alex??? #1l5x print(‘alex‘.translate(password)) print(‘alex‘.replace(‘l‘,"L")) print(‘alexl‘.replace(‘l‘,"L",1)) print(‘alex li‘.rfind(‘1‘)) print(‘aleEXSSnn‘.title()) #Aleexssnn
#split print(‘alex is LI‘.split()) #[‘alex‘, ‘is‘, ‘LI‘] print(‘alex is LI‘.split(‘l‘)) #[‘a‘, ‘ex is LI‘] print(‘1+2+4‘.split(‘+‘)) #[‘1‘, ‘2‘, ‘4‘] print(‘1+2\n+4‘.splitlines()) #[‘1+2‘, ‘+4‘] print(‘1+2\n+4‘.split()) #[‘1+2‘, ‘+4‘]
5.字典 dict
#初始化dict
dic = dict.fromkeys([6,7,8])
print(dic)
#{8: None, 6: None, 7: None}
dic1 = dict.fromkeys([6,7,8],‘test‘)
print(dic1)
#{8: ‘test‘, 6: ‘test‘, 7: ‘test‘}
dic2 = dict.fromkeys([6,7,8],[11,{‘alex‘:33},‘ssss‘])
print(dic2)
#{8: [11, {‘alex‘: 33}, ‘ssss‘], 6: [11, {‘alex‘: 33}, ‘ssss‘], 7: [11, {‘alex‘: 33}, ‘ssss‘]}
info = {
‘name‘:‘alex‘,
‘age‘:‘23‘,
‘job‘:‘it‘,
‘sal‘:‘1111‘,
}
print(info) # k :v 无序的
#key value item print(info.keys()) print(info.values()) print(info.items()) # dict_keys([‘job‘, ‘name‘, ‘sal‘, ‘age‘]) # dict_values([‘it‘, ‘alex‘, ‘1111‘, ‘23‘]) # dict_items([(‘job‘, ‘it‘), (‘name‘, ‘alex‘), (‘sal‘, ‘1111‘), (‘age‘, ‘23‘)])
#查找 print(info.get(‘sss‘,None)) #print(info[‘sss‘]) #KeyError: ‘sss‘ print(‘23‘ in info)#False print(‘age‘ in info)#True
#改 增 info[‘age‘]=‘66‘ print(info) info[‘snake‘]=‘we‘ print(info)
#删除 del info[‘age‘] print(info) info.pop(‘name‘) print(info)
#合并 两个字典
b = {
‘stu‘:‘jack‘,
‘saving‘:‘2000‘,
‘course‘:‘python‘,
}
info.update(b)
print(info)
#{‘snake‘: ‘we‘, ‘sal‘: ‘1111‘, ‘stu‘: ‘jack‘, ‘course‘: ‘python‘, ‘saving‘: ‘2000‘, ‘job‘: ‘it‘}
#嵌套 三维字典
av_msg = {
‘we‘:{
‘top‘:[‘957‘,‘v‘],
‘jug‘:[‘condi‘,‘mlxg‘],
‘mid‘:[‘xiye‘,‘xiaohu‘]
},
‘edg‘:{
‘xia‘:[‘zet‘,‘zhao‘],
‘jug‘:[‘loli‘,‘clearlove‘],
‘top‘:[‘mouse‘,‘audi‘]
},
‘rng‘:{
‘top‘:[‘letme‘,‘kornal‘],
‘xia‘:[‘y4‘,‘uzi‘],
‘fuzhu‘:[‘ming‘,‘ning‘]
}
}
#修改
print(av_msg)
av_msg[‘rng‘][‘top‘][0]=‘longlong‘
print(av_msg)
#增加
av_msg.setdefault(‘ig‘,{‘top‘:[‘sky‘,‘skey‘]}) #增加一条
av_msg.setdefault(‘rng‘,{‘top‘:[‘sky‘,‘skey‘]}) #如果存在rng，则不添加
print(av_msg)
#循环打印key
for k in av_msg:
print(k)
#ig
# edg
# we
# rng
#循环打印value
for v in av_msg:
print(av_msg[v])
#字典转换成列表，不推荐使用
for k,v in av_msg.items():
print(k,v)
# for index,item in enumerate(av_msg)
for index,item in enumerate(av_msg):
print(index,item)
# 0 rng
# 1 ig
# 2 we
# 3 edg
for index,item in enumerate(av_msg):
print(index,item,av_msg[item])
#0 edg {‘xia‘: [‘zet‘, ‘zhao‘], ‘jug‘: [‘loli‘, ‘clearlove‘], ‘top‘: [‘mouse‘, ‘audi‘]}
#1 ig {‘top‘: [‘sky‘, ‘skey‘]}
#2 rng {‘top‘: [‘longlong‘, ‘kornal‘], ‘xia‘: [‘y4‘, ‘uzi‘], ‘fuzhu‘: [‘ming‘, ‘ning‘]}
#3 we {‘mid‘: [‘xiye‘, ‘xiaohu‘], ‘top‘: [‘957‘, ‘v‘], ‘jug‘: [‘condi‘, ‘mlxg‘]}
作业三：多级菜单
三级菜单
可依次选择进入各子菜单
所需新知识点：列表、字典
‘‘‘
info ={ ‘China‘:{ ‘陕西‘:{ ‘西安‘:[‘小寨‘,‘雁塔‘,‘高新‘], ‘咸阳‘:[‘乾陵‘,‘昭陵‘,‘武陵‘], ‘渭南‘:[‘渭水‘,‘华山‘,‘黄河‘], }, ‘江苏‘:{ ‘昆山‘:[‘统一‘,‘康师傅‘,‘三一‘], ‘上海‘:[‘机场‘,‘英语‘,‘明珠‘], ‘南京‘:[‘大桥‘,‘长江‘,‘渔船‘], }, ‘北京‘:{ ‘北京市‘:[‘长城‘,‘故宫‘,‘颐和园‘], ‘天津‘:[‘炮台‘,‘海港‘,‘包子‘], ‘烟台‘:[‘海滩‘,‘大海‘,‘海鲜‘], }, }, ‘USA‘:{‘埃塞尔州‘:{‘洛杉矶‘:[‘湖人‘,‘火箭‘,‘勇士‘]}}, ‘Europe‘:{‘莱茵河‘:{‘英国‘:[‘神奇女侠‘,‘希特勒‘,‘诺曼底‘]}} } while True: for item in info: print(item) choice_1 = input(‘choice_1 [q|.]>‘).strip() if choice_1 in info: while True: for i in info[choice_1]: print(‘\t‘,i) choice_2 = input(‘\tchoice_2 [q|e|.]>‘).strip() if choice_2 in info[choice_1]: while True: for i in info[choice_1][choice_2]: print(‘\t\t‘,i) choice_3 = input(‘\t\tchoice_3 [q|e|.]>‘).strip() if choice_3 in info[choice_1][choice_2]: while True: print(‘\t\t\t‘,info[choice_1][choice_2][choice_3]) choice_4 = input(‘this is bottom [ q | e]>‘) if choice_4 == ‘q‘: break elif choice_4 == ‘e‘: exit() elif choice_3 == ‘q‘: break elif choice_3 == ‘e‘: exit() elif choice_2 == ‘q‘: break elif choice_2 == ‘e‘: exit() elif choice_1 == ‘q‘: exit()
‘‘‘ 如何获取dict 下标对应的item ‘‘‘
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