主要內容：
　　for循環

　　while循環

　　格式化輸出(2)

　　數據統計及記錄

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1、for循環

(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循環正常執行則執行else中的內容
# exit("too many attempt")
# print("welcome two")

驗證：
F:\Python\Python3\python.exe D:/python培訓/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退出本次循環，繼續下一次循環
# else:
# for j in range(10):
# if j<8:
# continue
# # continue退出本次循環，繼續下一次循環
# else:
# print(i,j)

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

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2、while循環

#while循環
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 = ["張三","李四","王五","趙六"]
name1 = name.copy()
name2 = name
print(name,id(name),"原值","\n",name1,id(name1),"copy值","\n",name2,id(name2),"賦值")

驗證：

F:\Python\Python3\python.exe D:/python培訓/our_python/day2/test.py
age>>:56
OK
['張三', '李四', '王五', '趙六'] 2561688 原值
['張三', '李四', '王五', '趙六'] 2525864 copy值
['張三', '李四', '王五', '趙六'] 2561688 賦值

3、格式化輸出(2)

msg='hello word'
print(msg[4])
#首字母大寫
print(msg.capitalize())
#輸出占用20個位置，居中顯示，*號占位，默認空格占位
print(msg.center(20,'*'))
#統計第4位到第10位l的個數
print(msg.count('l',4,10))
#檢測字符串是否以某個字符結尾
print(msg.endswith('d'))

msg1='a\tb'
#指定tab鍵占用的空格數
print(msg1.expandtabs('10'))
#檢測字符串中某個字符的位置
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、數據統計及記錄
#統計列表
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)

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

#輸出系統當前時間
import time
print (time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))

#將字典中的數據寫入文件，更新時將上次數據直接覆蓋
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)

#將文件中的數據讀入字典
f = open('C:\\Users\\admin\\Desktop\\shopping_Dict.txt', 'r')
f.seek(0,0)
for line in f.readlines():
print("上次購買商品為[商品名:數量]：")
L=list(map(str, line.split(';')))
# print(L)
for i in range(len(L)):
print (L[i])
f.close()

#不同人的結果輸入到不同的文件
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("購買時間為:%s;" % date)
DD.close()

#balance
f3 = "C:\\\\Users\\\\admin\\\\Desktop\\\\shopping_Dict_balance_%s.txt" % name_input
BD = open(f3,'w')
BD.writelines("卡上余額為:%s;" % salary)
BD.close()
###############################################################################################
#不同人登錄、輸出各自的購買信息；首次登錄或者未購買物品則輸出為“目前還沒有購買過任何物品”
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("上次購買商品[商品名:數量]：".center(50,'-'))
L=list(map(str, line.split(';')))
# print(L)
for i in range(len(L)):
print (L[i])
S1.close()
else:
print("目前還沒有購買過任何物品")


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("上次購買商品時間".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("上次購買商品后卡上余額".center(50,'-'))
L=list(map(str, line.split(';')))
# print(L)
for i in range(len(L)):
print (L[i])
S3.close()

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轉載于:https://www.cnblogs.com/feiyu_Team/p/5984426.html

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