标签：空格 切片 元素 product pre 购物 添加 其他 map
一、元组
另一种有序列表叫元组：tuple。tuple和list非常类似，但是tuple一旦初始化就不能修改，比如同样是列出同学的名字：
# Author:Tim Gu tuple = ("Tim",‘Jack‘,‘mike‘)
元组元素不可被修改，只读。不过有一种情况是内嵌列表的时候，列表内的元素可修改
# Author:Tim Gu tuple = ("Tim",‘Jack‘,‘mike‘,[‘john‘,‘tom‘]) print(tuple) tuple[3][1] = ‘mary‘ print(tuple) >>> (‘Tim‘, ‘Jack‘, ‘mike‘, [‘john‘, ‘tom‘]) (‘Tim‘, ‘Jack‘, ‘mike‘, [‘john‘, ‘mary‘])
二、字符串
输入时的空格处理：
# Author:Tim Gu username = input(‘user:‘) if username.strip() == ‘Tim‘: #去除输入时的空格 print("welcome")
输出：
user: Tim
welcome
字符串的拆分与合成：
names = ‘Tim,jack,rain‘ name2 = names.split(",") #拆分 print(name2) print(",".join(name2)) #组合 >>> [‘Tim‘, ‘jack‘, ‘rain‘] Tim,jack,rain
判断字符串有没有空格
# Author:Tim Gu name = ‘Tim Gu‘ if ‘‘ in name: print(‘‘ in name) >>>True
字符串的格式化：format()
msg = "Hello, {name}, it‘s been a long {age} since time sopke..." msg2 = msg.format(name=‘Tim‘,age=30) print(msg2) >>> Hello, Tim, it‘s been a long 30 since time sopke...
msg2 = "hahaha{0}, ddd{1}" print(msg2.format("Tim",33)) >>> hahahaTim, ddd33
字符串切片
name = ‘tim gu‘ print(name[1:3]) #打印序列字符 print(name.center(40,‘-‘)) #填满40个字符 print(name.find(‘m‘)) #搜索字符串中的字符，返回的第一个找到的值的索引，没有找到返回-1 print(name.find(‘b‘)) >>> im -----------------tim gu----------------- 2 -1
判断输入是否数字
age = input(‘input you age:‘) if age.isdigit(): #判断输入是否是数字 age = int(age) else: print(‘Invalid data type‘) >>> age = input(‘input you age:‘) if age.isdigit(): #判断输入是否是数字 age = int(age) else: print(‘Invalid data type‘)
判断输入是否包含特殊字符
name = ‘Timsjl4‘ print(name.isalnum()) >>> True
字符特殊判断
name = ‘Timsjl4‘ print(name.endswith(‘jl4‘)) #判断是否jl4结尾 print(name.startswith(‘Tim‘)) #判断是否Tim开头 print(name.upper()) #大写 print(name.lower()) #小写 >>> True True TIMSJL4 timsjl4
三、运算：
运算符：
+ 加
- 减
* 乘
/ 除
** 幂
% 取摸--返回除法的余数
// 取整数---返回商的整数
比较运算：
== 等于
!= 不等于
>= 大于等于
<=小于等于
> 大于
< 小于
赋值运算：
= 赋值
+=加法赋值
-=减法赋值
*=乘法赋值
/=除法赋值
%=取模赋值
**=幂赋值
//取整除赋值
逻辑运算：
and 与---条件全为真返回True
or 或 -----条件有一个为True，返回True
not 布尔非
分身运算：
is 判断两个标识符是否引用自一个对象
is not 判断两个标识符是不是发引用不同对象
位运算：
& 按位与运算符
| 按位或运算符
^ 按位异或运算符
~ 按位取反运算符
<< 左移动运算符
>> 右移动运算符
四、字典
Python内置了字典：dict的支持，dict全称dictionary，在其他语言中也称为map，使用键-值（key-value）存储，具有极快的查找速度。
字典中的key必须是唯一的。
id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } print(id_db) id_db[9527][‘name‘] = ‘jeson‘ #修改key print(id_db[9527]) id_db[9531][‘wife_qq‘] = 59594399 #增加key和值 print(id_db[9531]) del id_db[9520][‘addr‘] #删除key和值 print(id_db[9520]) id_db[9527].pop(‘addr‘) #删除key和值 等同于上面的del print(id_db[9527])
输出：
{9520: {‘age‘: 23, ‘name‘: ‘Jack‘, ‘addr‘: ‘SuZhou‘}, 9531: {‘age‘: 30, ‘name‘: ‘Mike‘, ‘addr‘: ‘NanJing‘}, 9527: {‘age‘: 22, ‘name‘: ‘Tim‘, ‘addr‘: ‘ShangHai‘}}
{‘age‘: 22, ‘name‘: ‘jeson‘, ‘addr‘: ‘ShangHai‘}
{‘age‘: 30, ‘name‘: ‘Mike‘, ‘wife_qq‘: 59594399, ‘addr‘: ‘NanJing‘}
{‘age‘: 23, ‘name‘: ‘Jack‘}
{‘age‘: 22, ‘name‘: ‘jeson‘}
获取值：get()
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } print(id_db) v = id_db.get(9531) #一般使用get获取值 #v = id_db[9531]#不建议使用这个 print(v)
输出：
{9520: {‘name‘: ‘Jack‘, ‘addr‘: ‘SuZhou‘, ‘age‘: 23}, 9531: {‘name‘: ‘Mike‘, ‘addr‘: ‘NanJing‘, ‘age‘: 30}, 9527: {‘name‘: ‘Tim‘, ‘addr‘: ‘ShangHai‘, ‘age‘: 22}}
{‘name‘: ‘Mike‘, ‘addr‘: ‘NanJing‘, ‘age‘: 30}
update()
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } dist2 = { 9527:{ ‘name‘:‘zhangsan‘, ‘age‘:10, ‘addr‘:‘JiangXi‘ } } print(id_db) id_db.update(dist2) print(id_db)
输出： 如果存在相同的key值，即覆盖。如不存在，则新建
{9520: {‘age‘: 23, ‘addr‘: ‘SuZhou‘, ‘name‘: ‘Jack‘}, 9531: {‘age‘: 30, ‘addr‘: ‘NanJing‘, ‘name‘: ‘Mike‘}, 9527: {‘age‘: 22, ‘addr‘: ‘ShangHai‘, ‘name‘: ‘Tim‘}}
{9520: {‘age‘: 23, ‘addr‘: ‘SuZhou‘, ‘name‘: ‘Jack‘}, 9531: {‘age‘: 30, ‘addr‘: ‘NanJing‘, ‘name‘: ‘Mike‘}, 9527: {‘age‘: 10, ‘addr‘: ‘JiangXi‘, ‘name‘: ‘zhangsan‘}}
返回字典中的key或值，判断KEY是否存在：
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } print(id_db) print(id_db.values()) print(id_db.keys()) print(9527 in id_db)
输出：
{9520: {‘addr‘: ‘SuZhou‘, ‘age‘: 23, ‘name‘: ‘Jack‘}, 9531: {‘addr‘: ‘NanJing‘, ‘age‘: 30, ‘name‘: ‘Mike‘}, 9527: {‘addr‘: ‘ShangHai‘, ‘age‘: 22, ‘name‘: ‘Tim‘}}
dict_values([{‘addr‘: ‘SuZhou‘, ‘age‘: 23, ‘name‘: ‘Jack‘}, {‘addr‘: ‘NanJing‘, ‘age‘: 30, ‘name‘: ‘Mike‘}, {‘addr‘: ‘ShangHai‘, ‘age‘: 22, ‘name‘: ‘Tim‘}])
dict_keys([9520, 9531, 9527])
True
set.default():
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } print(id_db.setdefault(9527)) #取一个key print(id_db.setdefault(9333,‘dddd‘)) #如果不存在，新增一个默认的key和值
输出：
{‘age‘: 22, ‘addr‘: ‘ShangHai‘, ‘name‘: ‘Tim‘}
dddd
随机删除：popitem()
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } print(id_db.popitem()) #随机删除一组数据 print(id_db)
输出：
(9520, {‘name‘: ‘Jack‘, ‘addr‘: ‘SuZhou‘, ‘age‘: 23})
{9531: {‘name‘: ‘Mike‘, ‘addr‘: ‘NanJing‘, ‘age‘: 30}, 9527: {‘name‘: ‘Tim‘, ‘addr‘: ‘ShangHai‘, ‘age‘: 22}}
字典转化为元组：items()
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } print(id_db.items()) >>> dict_items([(9520, {‘name‘: ‘Jack‘, ‘age‘: 23, ‘addr‘: ‘SuZhou‘}), (9531, {‘name‘: ‘Mike‘, ‘age‘: 30, ‘addr‘: ‘NanJing‘}), (9527, {‘name‘: ‘Tim‘, ‘age‘: 22, ‘addr‘: ‘ShangHai‘})])
字典的循环：
# Author:Tim Gu id_db = { 9527:{ ‘name‘:‘Tim‘, ‘age‘:22, ‘addr‘:‘ShangHai‘ }, 9520:{ ‘name‘:‘Jack‘, ‘age‘:23, ‘addr‘:‘SuZhou‘ }, 9531:{ ‘name‘:‘Mike‘, ‘age‘:30, ‘addr‘:‘NanJing‘ } } for key in id_db: print(key,id_db[key])
输出：
9520 {‘age‘: 23, ‘name‘: ‘Jack‘, ‘addr‘: ‘SuZhou‘}
9531 {‘age‘: 30, ‘name‘: ‘Mike‘, ‘addr‘: ‘NanJing‘}
9527 {‘age‘: 22, ‘name‘: ‘Tim‘, ‘addr‘: ‘ShangHai‘}
五、集合 set
set和dict类似，也是一组key的集合，但不存储value。由于key不能重复，所以，在set中，没有重复的key。
创建一个set
# Author:Tim Gu s = set({1,3,4,5}) s2 = {1,2,3,4} print(type(s)) print(s) print(type(s2)) print(s2) >>> <class ‘set‘> {1, 3, 4, 5} <class ‘set‘> {1, 2, 3, 4}
s2其实是调用了set()的构造方法
列表转化集合：
li = [11,22,11,22] s1 = set(li) print(s1)
输出：
{11, 22}
注意：集合是没有重复值的
集合添加元素：
se = {1,2,5,6,4}
se.add(3)
print(se)
>>>
{1, 2, 3, 4, 5, 6}
集合删除元素：
se = {1,2,5,6,4}
se.remove(5) #删除，如果5不存在，报错
se.discard(2)#删除，如果2不存在，不报错
print(se)
>>>
{1, 4, 6}
集合是无序的无重复的元素的集合，所以两个set可以做交集、并集等操作：
se1 = {1,2,5,6,4}
se2 = {5,6,8,3,44}
print(se1&se2)
print(se1|se2)
>>>
{5, 6}
{1, 2, 3, 4, 5, 6, 8, 44}
差集：
s1 = {11,22,33}
s2 = {22,33,44}
s4 = {33,44,55}
s3 = s1.difference(s2)
print(s3) #s1中存在，s2中不存在
s3 = s1.symmetric_difference(s2) #d对称差集
print(s3)
s1.difference_update(s2) #将s1更新为s1和s2的差集
print(s1)
输出：
{11}
{11, 44}
{11}
s1 = {11,22,33}
s2 = {22,33,44}
s1.symmetric_difference_update(s2) #将s1更新为s1和s2的对称差集
print(s1)
>>>
{11, 44}
pop移除：
s1 = {11,22,33}
ret = s1.pop() #因集合是无序的，pop()会随机移除元素，将移除的元素赋给ret
print(s1)
print(ret)
>>>
{11, 22}
33
并集：
s1 = {11,22,33}
s2 = {22,33,44}
s3 = s1.union(s2)
print(s3)
>>>
{33, 22, 11, 44}
update()
s1 = {11,22,33}
li = [11,22,3,11,2]
s1.update(li)
print(s1)
s = ‘tim‘
s1.update(s)
print(s1)
>>>
{3, 33, 2, 11, 22}
{33, 2, 3, ‘t‘, ‘i‘, 11, ‘m‘, 22}
第二周练习：完美购物车
要求：
购物车：
用户启动程序后打印商品列表
允许用户选择购买商品
允许用户不断地购买各种商品
购买时检测 余额是否足够，如果足够，直接扣款 否则打印余额不足
允许用户主动退出程序，退出时打印已购商品列表
# Author:Tim Gu for i in range(3): salary = input(‘Input your salary:‘) if salary.isdigit(): salary = int(salary) break else: print(‘Invaild data type...‘) if i == 2: print(‘Wrong!‘) continue welcome_msg = ‘Welcome to Tim Shopping mall‘.center(50, ‘-‘) print(welcome_msg) exit_flag = False product_list = [ (‘Iphone‘,5888), (‘Mac Air‘,8000), (‘mac pro‘,9000), (‘xiaomi 2‘,19.2), (‘Coffer‘,30), (‘Tesla‘,820000), (‘Bike‘,700), (‘Cloth‘,200) ] shop_car = [] while exit_flag != True: print(‘product list‘.center(50,‘-‘)) for item in enumerate(product_list):#枚举元组 index = item[0] p_name = item[1][0] p_price = item[1][1] print(index,p_name,p_price) user_choice = input(‘[q=quit,c=check]What do you watn to buy?:‘) if user_choice.isdigit():#肯定是选择商品 user_choice = int(user_choice) if user_choice < len(product_list): p_item = product_list[user_choice] if p_item[1] <= salary: #资金够买 shop_car.append(p_item) salary -= p_item[1] print(‘Added [%s] into shop car,you current balance is \033[31;1m[%s]\033[0m‘%( p_item[0],salary)) else: print("Your balance is [%s],cannot afford this..."%salary) elif user_choice == ‘q‘ or user_choice == ‘quit‘: print("purchased products as below".center(40,‘*‘)) for item in shop_car: print(item) print("END".center(40,‘*‘)) print("Your balance is [%s] last"%salary) exit_flag = True elif user_choice == ‘c‘ or user_choice == ‘check‘: print("purchased products as below".center(40, ‘*‘)) for item in shop_car: print(item) print("END".center(40, ‘*‘)) print("Your balance is \033[41;1m[%s] last\033[0m" % salary)
作业需求：
作业需求： 1.优化购物程序，购买时允许用户选择购买多少件
2.允许多用户登陆，下一次登录后，继续按上次的余额继续购买（可以充值）
3.允许多户查看之间的购买记录（记录要显示商品购买时间）
4.商品列表分级展示，比如 第一层菜单： 1.家电类 2.衣服 3.手机类 4.车类
随便选择一个，比如车类，进入第2层
1.BMW X3 300000
2.AUDI Q5 350000
3.pasate 333335
4 tesla model_3 430000
5.tesla model_s 8888888
5.显示已购买商品时，如果有重复的商品，不打印多行，而是在一行展示
id p_name num total_price
1. TeslaModelS 2 35000000
2. coffee 4 10000
标签：空格 切片 元素 product pre 购物 添加 其他 map
原文地址：http://www.cnblogs.com/guqing/p/6071885.html
