if_else_while

if_else_while_for

 1 import getpass
 2 #标准库里要加密密码需要导包getpass.但是getpass在pycharm中不好用,需要在命令窗口中输入才管用.
 3 
 4 _username = "abc"
 5 _password = "abc123"
 6 username = input("username:")
 7 # password = getpass.getpass("password:")
 8 password = input("password:")
 9 
10 if _username==username and _password==password:
11     print("Welcome user {name} login...".format(name=username))
12 else:
13     print("invalid username or password")

 1 age_of_oldboy = 56
 2 
 3 guess_age = int(input("guess age:"))
 4 
 5 if guess_age==age_of_oldboy:
 6     print("yes, you got it.")
 7 elif guess_age>age_of_oldboy:
 8     print("think smaller")
 9 else:
10     print("think bigger")

 1 age_of_oldboy = 56
 2 
 3 count=0
 4 while True:
 5     if count==3:
 6         break
 7     # print("count:",count)
 8     guess_age = int(input("guess age:"))
 9 
10     if guess_age==age_of_oldboy:
11         print("yes, you got it.")
12         break
13     elif guess_age>age_of_oldboy:
14         print("think smaller")
15     else:
16         print("think bigger")
17     count=count+1  #count+=1
18 if count==3:
19     print("you have tried too many times! Fuck off!")
20 
21 
22 # 优化后的代码
23 while count<3:
24     guess_age = int(input("guess age:"))
25 
26     if guess_age==age_of_oldboy:
27         print("yes, you got it.")
28         break
29     elif guess_age>age_of_oldboy:
30         print("think smaller")
31     else:
32         print("think bigger")
33     count=count+1  #count+=1
34 else:
35     print("you have tried too many times! Fuck off!")

 1 '''
 2 while循环实现
 3 age_of_oldboy = 56
 4 
 5 count=0
 6 while True:
 7     if count==3:
 8         break
 9     # print("count:",count)
10     guess_age = int(input("guess age:"))
11 
12     if guess_age==age_of_oldboy:
13         print("yes, you got it.")
14         break
15     elif guess_age>age_of_oldboy:
16         print("think smaller")
17     else:
18         print("think bigger")
19     count=count+1  #count+=1
20 if count==3:
21     print("you have tried too many times! Fuck off!")
22 
23 
24 # 优化后的代码
25 while count<3:
26     guess_age = int(input("guess age:"))
27 
28     if guess_age==age_of_oldboy:
29         print("yes, you got it.")
30         break
31     elif guess_age>age_of_oldboy:
32         print("think smaller")
33     else:
34         print("think bigger")
35     count=count+1  #count+=1
36 else:
37     print("you have tried too many times! Fuck off!")
38 
39 '''
40 '''
41 for i in range(10):   #range10其实是从0到9.
42     print("loop", i)
43 '''
44 
45 # for循环来实现
46 age_of_oldboy = 56
47 for i in range(3):
48     guess_age = int(input("guess age:"))
49     if guess_age == age_of_oldboy:
50         print("yes, you got it")
51         break
52     elif guess_age > age_of_oldboy:
53         print("think smaller")
54     else:
55         print("think bigger")
56 else:
57     print("you have tried too many times.. fuck off!")

1 # 0到9的数字,隔一个打印一个到控制台
2 for i in range(0,10,2):   #括号中的2是步长,不写的话默认是1.若想隔两个打印一uqw,则步长设置为3即可.即for i in range(0,10,3)
3     print("loop", i)

 1 # 每错三次不直接跳出,而是问玩家是否要继续
 2 age_of_oldboy = 56
 3 
 4 count=0
 5 while True:
 6     if count==3:
 7         break
 8     # print("count:",count)
 9     guess_age = int(input("guess age:"))
10 
11     if guess_age==age_of_oldboy:
12         print("yes, you got it.")
13         break
14     elif guess_age>age_of_oldboy:
15         print("think smaller")
16     else:
17         print("think bigger")
18     count=count+1  #count+=1
19     if count==3:
20         continue_confirm = input('do you want to continue?')
21         if continue_confirm !='n':
22             count=0
23 else:
24     print("you have tried too many times! Fuck off!")

1 # continue的用法: 跳出本次循环,继续下一次循环
2 for i in range(0,10):
3     if i<5:
4         print("loop", i)
5     else:
6         continue  #跳出本次循环,继续下一次循环
7     print("hehe...")

1 #break:结束当前循环
2 for i in range(10):
3     print("-----------------",i)
4     for j in range(10):
5         print(j)
6         if j>5:
7             break