一、while循环
while 条件:
条件为真执行的语句
esle:
条件为假执行的语句
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:Hiuhung Wan count = 0 while count < 100: print("Count:",count) count += 1
猜年龄升级版
1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 # Author:Hiuhung Wan 4 age_of_MrWang = 48 5 count = 0 6 while count < 3: 7 guess_age = int(input("Enter the age of Mr Wang:")) 8 if guess_age == age_of_MrWang: 9 print("Yes,you got it!") 10 break 11 elif guess_age < age_of_MrWang: 12 print("Think bigger!") 13 else: 14 print("Think smaller!") 15 count += 1 16 # if count == 3: 17 # print("You have tried too many times...Fuck off!") 18 else: 19 print("You have tried too many times...Fuck off!")
二、For循环
for i in range (xx):
语句
else:
上面循环里的语句正常走完了后,才执行这里的语句
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:Hiuhung Wan for i in range(10): print("loop",i)
再次优化一下猜年龄小程序
1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 # Author:Hiuhung Wan 4 age_of_MrWang = 48 5 for i in range (3): 6 guess_age = int(input("Enter the age of Mr Wang:")) 7 if guess_age == age_of_MrWang: 8 print("Yes,you got it!") 9 break 10 elif guess_age < age_of_MrWang: 11 print("Think bigger!") 12 else: 13 print("Think smaller!") 14 else: 15 print("You have tried too many times...Fuck off!")
三、for循环步长问题
range里可以设置,默认是1
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:Hiuhung Wan for i in range(0,10,2): #步长是2 print("loop",i)
四、猜年龄小程序加入继续玩模式
思路:猜了三次还没有猜对,提示是否继续猜,如果按n就退出程序,其他键就继续猜。同时判断输入是否为数字
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:Hiuhung Wan age_of_MrWang = 48 count = 0 #计数器 while count < 3: guess_age = input("Enter the age of Mr Wang:") if guess_age.isdigit(): #输入了数字 guess_age = int(guess_age) if guess_age == age_of_MrWang: print("Yes,you got it!") break #猜对了,退出while循环 elif guess_age < age_of_MrWang: print("Think bigger!") else: print("Think smaller!") count += 1 if count == 3: continue_confirm = input("Do you want to keey guessing?") if continue_confirm != "n": count = 0 # 计数器清零 else: print("Please enter a number!")
五、break与continue
continue:跳出本次循环(或者说:结束当前循环),继续下一次循环
break:结束整个循环
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:Hiuhung Wan for i in range(0,10): if i < 5: print("loop",i) else: continue print("The variable i loops once")
六、for循环嵌套
注意break的使用
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:Hiuhung Wan for i in range(10): print("-------",i) for j in range (10): print(j) if j > 5: break #结束当前循环(j),继续下一次循环