主要内容：
　　for循环

　　while循环

　　格式化输出(2)

　　数据统计及记录

#############################################################

1、for循环

(A):

# #one_guess_age
# num_age = 40
# for i in range(3):
#     age_input = int(input("input age:"))
#     if num_age == age_input:
#         print ("OK")
#         break
#     elif age_input < num_age:
#         print("smaller")
#     else:
#         print("bigger")
# else: 
　　　　#for循环正常执行则执行else中的内容
#     exit("too many attempt")
# print("welcome two")

验证：
F:\Python\Python3\python.exe D:/python培训/our_python/day2/test.py
input age:0
smaller
input age:50
bigger
input age:40
OK
welcome two

(B)

# for i in range(3):
#     if i < 2:
#         continue
#         # continue退出本次循环，继续下一次循环
#     else:
#         for j in range(10):
#             if j<8:
#                 continue
#                 # continue退出本次循环，继续下一次循环
#             else:
#                 print(i,j)

验证：
F:\Python\Python3\python.exe D:/python培训/our_python/day2/test.py
2 8
2 9

2、while循环

#while循环
count = 0
oldboy_age=56

while count < 3:
    age_input = input("age>>:")
    if age_input.isdigit():
        age_input = int(age_input)
    else:
        count += 1
        continue
    if age_input == oldboy_age:
        print("OK")
        break
    elif age_input > oldboy_age:
        print("try small")
    else:
        print("try big")
    count +=1
name = ["张三","李四","王五","赵六"]
name1 = name.copy()
name2 = name
print(name,id(name),"原值","\n",name1,id(name1),"copy值","\n",name2,id(name2),"赋值")

验证：

F:\Python\Python3\python.exe D:/python培训/our_python/day2/test.py
age>>:56
OK
['张三', '李四', '王五', '赵六'] 2561688 原值
['张三', '李四', '王五', '赵六'] 2525864 copy值
['张三', '李四', '王五', '赵六'] 2561688 赋值

3、格式化输出(2)

msg='hello word'
print(msg[4])
#首字母大写
print(msg.capitalize())
#输出占用20个位置，居中显示，*号占位，默认空格占位
print(msg.center(20,'*'))
#统计第4位到第10位l的个数
print(msg.count('l',4,10))
#检测字符串是否以某个字符结尾
print(msg.endswith('d'))

msg1='a\tb'
#指定tab键占用的空格数
print(msg1.expandtabs('10'))
#检测字符串中某个字符的位置
print(msg1.find('d',1,10))

# format()
print('{} {}'.format('name','age','sd'))
print('{name}'.format(name='zs'))
print('{0} {1} {0}'.format('name','age'))

4、数据统计及记录

#统计列表
a = [
    ['Ipone', 5800],
    ['bike', 2000],
    ['Coffee', 30],
    ['Coffee', 30],
    ['Coffee', 30],
    ['Coffee', 30]
]
b = {}
for i in range(len(a)):
    b[a[i][0]]=a.count(a[i])
print(b)

#统计字典
Dict = {'Ipone': 1, 'bike': 1, 'Coffee': 4}
for k,v in Dict.items():
    print(k,v)

#输出系统当前时间
import time
print (time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))

#将字典中的数据写入文件，更新时将上次数据直接覆盖
Dict = {'Coffee': 5, 'Ipone': 1, 'bike': 1}
with open('C:\\Users\\admin\\Desktop\\shopping_Dict.txt', 'w') as D:
    D.writelines([
        "%s:%d;" % item
        for item in Dict.items()
        ])
print (Dict)

#将文件中的数据读入字典
f = open('C:\\Users\\admin\\Desktop\\shopping_Dict.txt', 'r')
f.seek(0,0)
for line in f.readlines():
    print("上次购买商品为[商品名:数量]：")
    L=list(map(str, line.split(';')))
    # print(L)
    for i in range(len(L)):
        print (L[i])
f.close()

#不同人的结果输入到不同的文件
import time
name_input = input("please input Username:")
salary = input("money>>:")
date = time.strftime("%Y%m%d%H%M%S", time.localtime())
shopping_Dict = {'Coffee': 5, 'Ipone': 1, 'bike': 1}

f1 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_%s.txt" % name_input
SD = open(f1,'w')
SD.writelines(["%s:%d;" % item for item in shopping_Dict.items()])
SD.close()

f2 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_DATE_%s.txt" % name_input
DD = open(f2,'w')
DD.writelines("购买时间为:%s;" % date)
DD.close()

#balance
f3 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_balance_%s.txt" % name_input
BD = open(f3,'w')
BD.writelines("卡上余额为:%s;" % salary)
BD.close()
###############################################################################################
#不同人登录、输出各自的购买信息；首次登录或者未购买物品则输出为“目前还没有购买过任何物品”
import os
# name_input = input("please input Username:")
f1 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_%s.txt" % name_input
if os.path.exists(f1):
    S1 = open(f1, 'r')
    S1.seek(0,0)
    for line in S1.readlines():
        print("上次购买商品[商品名:数量]：".center(50,'-'))
        L=list(map(str, line.split(';')))
        # print(L)
        for i in range(len(L)):
            print (L[i])
    S1.close()
else:
    print("目前还没有购买过任何物品")

f2 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_DATE_%s.txt" % name_input
if os.path.exists(f2):
    S2 = open(f2, 'r')
    S2.seek(0,0)
    for line in S2.readlines():
        print("上次购买商品时间".center(50,'-'))
        L=list(map(str, line.split(';')))
        # print(L)
        for i in range(len(L)):
            print (L[i])
    S2.close()

f3 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_balance_%s.txt" % name_input
if os.path.exists(f3):
    S3 = open(f3, 'r')
    S3.seek(0,0)
    for line in S3.readlines():
        print("上次购买商品后卡上余额".center(50,'-'))
        L=list(map(str, line.split(';')))
        # print(L)
        for i in range(len(L)):
            print (L[i])
    S3.close()