python笔记二

一 运算符

1算术运算+ - * /  % ** //其中%为取余，**为取幂如2**10=1024    9//4=2

需要注意的是python2.7中如9/2=4 需要正确表示，则在开头添加

from __future__ import division 而python3中不需要9/2=4.5

2比较运算符 ==  !=  <>   >  <  >=  <=

3赋值运算=  +=  -=  *=  /=  %=    **=   //=

如a*=c  等同a=a*c      a**=c等同 a=a**c

4罗辑运算

与and   或or    非not

5成员运算

in  not in

 s = "the school"
 ret = "sc" in s
 print(ret)

显示为True

二 python的数据类型

数字（ int）字符(str) 列表 (list)字典（dict）元组( tuple)

元组和列表的最大区别是，元组不能修改，列表可以修改

一查看数据类型里的哪些方法

1 help(int)

help(str)

help(list)

help(dict)

help(tuple)

2 通过PyCharm编写程序按信ctrl鼠标点上去加鼠标左键，点击如下

3 快速注释 ctrl + /(选中所需要注释的行按ctrl加 / ，再按一遍就快速去掉注释)

数字类型(int)

如s = 3

ret = s + 2与ret=s.__add__(2)等值

"""
3二进制0000 0011 最少用2位表示，所以输出结果为2
"""
s = 3
print(s.bit_length())

bit_length()

============================================================================

字符类型(str)

移除空白

str1 = "     hello        "
ret = str1.strip()
print(str1)
print(ret)
注lstrip为右边空白，  rstrip为左边并肯strip括号里可以输入字符
如str1.strip("*")

分割字符

str1 = " hello nihao wang        "
ret = str1.split()
print(str1)
print(ret)
运行结果

hello nihao wang
['hello', 'nihao', 'wang']

取字符长度len()

str1 = " hello nihao wang        "

print(len(str1))
字符串查找
ret=str1.find("hel")
print(ret)找到返回1，没有找到返回-1
分割

str1 = " hello nihao wang        "
ret =str1.split("o")
print(ret)
运行结果

C:\Users\Administrator\AppData\Local\Programs\Python\Python35\python.exe H:/python17/s1.py
[' hell', ' niha', ' wang ']

字符串连接

str1 = "hello"
ret ="#".join(str1)
print(ret)
运行结果

C:\Users\Administrator\AppData\Local\Programs\Python\Python35\python.exe H:/python17/s1.py
h#e#l#l#o

替换replace

str1 = "hello"
ret ="#".join(str1)
print(ret)
ret1=ret.replace("#"," ")
print(ret1)
运行结果

C:\Users\Administrator\AppData\Local\Programs\Python\Python35\python.exe H:/python17/s1.py
h#e#l#l#o
h e l l o

最原始的字符串连接方式：str1 + str2
python 新字符串连接语法：str1, str2
奇怪的字符串方式：str1 str2
% 连接字符串：‘name:%s; sex: ' % ('tom', 'male')
字符串列表连接：str.join(some_list

==========================================================================================================================

列表类型list

增加

name_list=["Robert","Rose","Merry","Hanny"]
name_list.append("wang")
print(name_list)
运行结果
['Robert', 'Rose', 'Merry', 'Hanny', 'wang']

插入insert()

name_list=["Robert","Rose","Merry","Hanny"]
name_list.insert(name_list.index("Rose"),"tt")
print(name_list)
运行结果
['Robert', 'tt', 'Rose', 'Merry', 'Hanny']
其中index是索引确定位置
删除

name_list=["Robert","Rose","Merry","Hanny"]
name_list.remove("Merry")
print(name_list)
运行结果

C:\Users\Administrator\AppData\Local\Programs\Python\Python35\python.exe H:/python17/s1.py
['Robert', 'Rose', 'Hanny']

计数

name_list=["Robert","Rose","Merry","Hanny","Robert"]
ret=name_list.count("Robert")
print(ret)
运行结果
2
移除并赋值

name_list=["Robert","Rose","Merry","Hanny","Robert"]
ret=name_list.pop()
print(ret)
print(name_list)
运行结果

C:\Users\Administrator\AppData\Local\Programs\Python\Python35\python.exe H:/python17/s1.py
Robert
['Robert', 'Rose', 'Merry', 'Hanny']

排序

name_list=["Robert","Rose","Merry","Hanny","Robert"]
name_list.sort()
print(name_list)
运行结果

['Hanny', 'Merry', 'Robert', 'Robert', 'Rose']

 包含in

name_list=["Robert","Rose","Merry","Hanny","Robert"]
ret="Robert" in name_list
print(ret)
运行结果
True

长度len()

name_list=["Robert","Rose","Merry","Hanny","Robert"]
ret=len(name_list)
print(ret)
运行结果
5

循环

name_list=["Robert","Rose","Merry","Hanny","Robert"]
for ret in name_list:
   print(ret)

运行结果

Robert
Rose
Merry
Hanny
Robert

===================================================================================

元组(tuple)

由于无法修改只有两个

count()

name_tuple=("Robert","Rose","Merry","Hanny","Robert")
ret=name_tuple.count("Robert")
print(ret)
运行结果
2

index()

name_tuple=("Robert","Rose","Merry","Hanny","Robert")
ret=name_tuple.index("Robert",1,5)
print(ret)
运行结果
4

同样支持for循环

=========================================================================================================

字典dict

更新update()

person_dict={"name":"Robert","sex":"M","age":18}
person_dict.update({"name":"east"})
print(person_dict)

运行结果

{'sex': 'M', 'name': 'east', 'age': 18}

person_dict={"name":"Robert","sex":"M","age":18}
person_dict.update({"school":"east"})
print(person_dict)
运行结果
{'age': 18, 'school': 'east', 'name': 'Robert', 'sex': 'M'}
结论，如果对应的有键值对，则修改，没有则增加

删除键值

person_dict={"name":"Robert","sex":"M","age":18}
person_dict.pop("name")
print(person_dict)
运行结果
{'sex': 'M', 'age': 18}

for循环

person_dict={"name":"Robert","sex":"M","age":18}
for ret in person_dict :
   print(ret)
运行结果

age
sex
name

取值get()

  

person_dict={"name":"Robert","sex":"M","age":18}
print(person_dict.get("name"))
运行结果
Robert
取值

person_dict={"name":"Robert","sex":"M","age":18}
print(person_dict.values())
print(person_dict.keys())
运行结果
<class 'dict_values'>
dict_keys(['sex', 'age', 'name'])

pop获取并在字典中删除

person_dict={"name":"Robert","sex":"M","age":18}
print(person_dict)
ret=person_dict.pop("name")
print(ret)
print(person_dict)
运行结果

{'sex': 'M', 'name': 'Robert', 'age': 18}
Robert
{'sex': 'M', 'age': 18}

=========================================================================
其它
enumrate对迭大的对像加上序号

li=["笔记本","电脑","U盘"]
for k,v in enumerate(li,1):
    print(k,v)
ret= input("choose:")
print(li[int(ret)-1])

运行结果

1 笔记本
2 电脑
3 U盘
choose:2
电脑

for i in range(1,5):
   print(i)
运行结果

1
2
3
4

for i in range(5,1,-1):
   print(i)
运行结果

5
4
3
2

=========================================

有如下值集合 [11,22,33,44,55,66,77,88,99,90...]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中。
即： {'k1': 大于66的所有值, 'k2': 小于66的所有值}

#/usr/bin/env python3
li=[11,22,33,44,55,77,88,99,90,23]
dic={"k1":[],"k2":[]}
for i in li:
   if i > 66:
      dic["k1"].append(i)
   elif i < 66:
      dic["k2"].append(i)
print(dic)
===============================================================

查找列表中元素，移除每个元素的空格，并查找以 a或A开头 并且以 c 结尾的所有元素。

    li = ["alec", " aric", "Alex", "Tony", "rain"]

    tu = ("alec", " aric", "Alex", "Tony", "rain") 

    dic = {'k1': "alex", 'k2': ' aric',  "k3": "Alex", "k4": "Tony"}

 #!/usr/bin/env python3
 li = ["alec", " aric", "Alex", "Tony", "rain"]
 tu = ("alec", " aric", "Alex", "Tony", "rain")
 dic = {'k1': "alex", 'k2': ' aric', "k3": "Alex", "k4": "Tony"}

 s=' '.join(li)
 t=s.split()
 print(li)
 for i in t:
     if i[0] == "a" or i[0] =="A" and i[len(i)-1] =="c" :
         print(i)
 print("===============================================")
 print(tu)
 m=' '.join(tu)
 n=m.split()
 for i in n:
     if i[0] == "a" or i[0] == "A" and i[len(i)-1]=="c" :
         print(i)
 print("===============================================")
 print(dic)
 t1=[]
 for m1 in dic.values():
     t1.append(m1)
 print(t1)
 m2=' '.join(t1)
 n1=m2.split()
 for i1 in n1 :
     if i1[0] == "a" or i1[0]=="A" and i1[len(i1)-1]=="c":
         print(i1)
 print("=================================================")

输出商品列表，用户输入序号，显示用户选中的商品

    商品 li = ["手机", "电脑", '鼠标垫', '游艇']

 #!/usr/bin/env python3
 li = ["手机", "电脑", '鼠标垫', '游艇']
 for k,v in enumerate(li,1):
     print(k,v)

 while True :
     i = input("请输入商品:")
     if i.isnumeric():
        if int(i) > 0 and int(i) < 5 :
          print(li[int(i)-1])
          break
        else:
         print("pleae input again")
     else:
        print("please input again")

采购清单程序

 #!/usr/bin/env python3
 goods = [
     {"name": "电脑", "price": 1999},
     {"name": "鼠标", "price": 10},
     {"name": "游艇", "price": 20},
     {"name": "美女", "price": 998},
     {"name": "bus", "price": 10000},
     {"name": "house","price":80000}
 ]
 lism = [] #商品名
 lisn = [] #商品价格
 buy_lis=[]#所购买的清单
 cai=["采购物品","修改清单","结算","充值","退出"]

 def goods_look(list1,list2):  #查看可购买的商品清单，价格
      flag=True
      num=0
      print("序号 商品名称   单价")
      while flag:
        if num < len(list1):
         print(num+1,"   ",list1[num],'   ',list2[num])
        else:
         break
        num = num+1
 #####################################################
 def buy_look(s): #查看购买物品清单
     i = 0
     print("序号    商品名称   单价     数量     金额")
     while i < len(s):
         for t in s[i]:
             t = s[i]
             for l in t.keys():
                 print(i+1,'    \t',l,'  \t',t[l][0],'    \t',t[l][1],'   \t',t[l][2])
             i = i + 1
 #####################################################

 def buy_goods(s): #查看购买物品
     print("  商品名        单价     数量         金额")
     for i in s.keys():
         if s[i][1] != 0 :
           print(i.center(10), '  ', str(s[i][0]).center(5), '   ', str(s[i][1]).center(3), '       ',
               str(s[i][2]).center(5))
 ##############################################################
 def buy_sum(n):#求购买物品清单总额
     sum=0
     i=0
     while i < len(n) :
         for j in n[i].keys() :
             m = n[i][j][2]
             sum = sum + int(m)
         i=i+1
     return sum
 ################################################################
 # def init_buy(s_dict,m_list,n_list):
 #     flag=0
 #     for n1 in m_list:
 #        buy.setdefault(n1,[n_list[flag],0,0])
 #        flag += 1
 #################################################################
 def buy_list(buy_goods,m_list,n_list,m,n):
     #加入购特车m代表商品序号，n代表数量 m_list商品单，n_list代表商品价格,buy_goods为数组
     sum=n_list[m]*n
     buy_goods.append({m_list[m]:[n_list[m],n,sum,]})
 ################################################################
 def list_m(s):
    lism1=[]
    for i in s:
     lism1.append(i.get('name'))
    return lism1
 def list_n(s):
     lisn1=[]
     for i in s:
       lisn1.append(i.get('price'))
     return lisn1
 def buy_act(list_m,list_n,s):
 #购买商口行为 list_m为商口名称，list_n为单价，s为输入金额
     flag2=True
     while flag2:
         goods_look(list_m,list_n)
         s1 = input("请输入商品序号：")
         s2 = input("请选择购买数量：")
         m = int(s1) - 1
         n = int(s2)
         buy_list(buy_lis, lism, lisn, m, n)
         buy_look(buy_lis)
         # sum1 = buy_sum(buy_lis)
         # print("你共计消费总额：", sum1, "还余：", s-sum1)
         # if sum1 < s:
         flag1 = input("是否需要继续购买Y/N：")
         if flag1 == 'Y':
             flag2 = True
         else:
             flag2 = False
         # else:
         #     s1 = input("请充值:")
         #     s += int(s1)
 def buy_cz(s):
     s1 = input("请充值:")
     s = int(s1)+s
     return s
 #======================================
 def buy_remove(s):  #移除不需要的商品
     print("您已选购如下商品")
     while True:
         buy_look(s)
         flag_y = input("请是否需要删除不需要的商品y/n")
         if flag_y == 'y' and len(s):
             c = input("请选择所购买的商品序号:")
             buy_lis.remove(s[int(c) - 1])

         else:
             break
 #================================================================
 def buy_end(lis,s): #结算，lis为购物清单,s为输入金额
     js = input("是否要去结算(y/n):")
     if js == 'y':

         sum2 = buy_sum(lis)  # 求和
         buy_look(lis)
         print("你共计消费总额：", sum2, "还余：", s - sum2)
     else:
         lis.clear()
         print(lis)
         print("你共计消费总额：", 0, "还余：", s)
 #================================================================
 def menu(lis):
     for k,v in enumerate(lis,1):
        print(k,v)

 #################################################################
 lism=list_m(goods)
 lisn=list_n(goods)
 goods_look(lism,lisn)
 ################################################################
 s=input("请输入金额:")
 input_s=int(s)
 # caidan(cai)
 while True :
     menu(cai)
     cai_s=input("请从上面的菜单选择(1-5):")
     if cai_s == "" :
         buy_act(lism,lisn,input_s)
     if cai_s == "" :
         if len(buy_lis):
             buy_remove(buy_lis)
         else:
             print("请重新选择")
             continue
     if cai_s == "" :
         if len(buy_lis):
             if buy_sum(buy_lis) <= input_s :
                 buy_end(buy_lis, input_s) #结算付款
                 temp=input_s - buy_sum(buy_lis)#付款余额
                 input_s = temp
                 buy_lis.clear()#清空购买物品list数组
             else:
                 print("余额不足请充值")
                 input_s = buy_cz(input_s)
                 print("余额为:",input_s)
         else:
             print("还没有购买请重新选择")
             continue
     if cai_s == "" :
         input_s = buy_cz(input_s)
         print("余额为:",input_s)
     if cai_s == "" :
         break

三级连动，输入一个县级市 查看属于哪个省哪个市

 #!/usr/bin/env python3
 dic = {
     "河北": {
         "石家庄": ["鹿泉", "藁城", "元氏"],
         "邯郸": ["永年", "涉县", "磁县"],
     },
     "湖北": {
         "武汉": ["武昌", "汉口", "汉阳"],
         "荆州": ["洪湖", "监利", "沙市"],
     },
     "广东":{
         "深圳":["罗湖","福田","南山","盐田"]
     },
 }
 lis1 = []
 lis2 = []
 s=input("please input country:")
 flag=True  #标识符，没有查到为真，找到了设为假
 for i in dic.keys():
     for j in dic[i].keys():
         lis2.append(j)
         k = 0
         while k < len(dic[i][j]):
             # lis2.clear() 创建 新的数组
             # lis2.append(i)
             # lis2.append(j)
             #
             # # lis2.append(j)
             #
             # lis2.append(dic[i][j][k])
             #
             # print(lis2)
             # lis1.append([lis2[0], lis2[1], lis2[2]])
             # print(i, '\t', j, '\t', dic[i][j][k])
             if s==dic[i][j][k]:
                 print(i,j,s)
                 flag=False
                 break
             k = k + 1

 if flag:
     print("系统中没有您所查的信息")