Python 学习第二章

print("我爱你，我的国！")

#班里面有10人，来了5人，现在有多少人？
student_number=10
come_number=5
new_number=student_number+come_number
print("班级现有",new_number,"人") # 没用字符串拼接

#班里面有10人，来了5人，现在有多少人？
student_number=10
come_number=5
new_number=student_number+come_number
print("班级现有"+str(new_number)+"人")  #采用字符串拼接

a = ["1","2","3","4"]
b = a[1]
c = a[0]
d = a[1:3]      #提取列表中 a[1]和a[2] 用到切片功能，后面在详细的学
print(b)    #b = 2
print(c)
print(d)      #d = ["2","3"]

age=(11,12,13,43,33,23)
print(age)

person={"name":"xp","age":24}
print(person)

1 ge_of_princal = 56   
2 guess_age = int(input(">>:"))
3 if guess_age == age_of_princal:
4     print("yes")
5 elif guess_age > age_of_princal:
6     print("太大了，往小的猜")
7 else:
8     print("太小了，往大的猜")

 1 score = int(input("score:"))
 2 
 3 if score > 90:
 4     print("A")
 5 elif score > 80:
 6     print("B")
 7 elif score > 70:
 8     print("C")
 9 elif score > 50:
10     print("D")
11 else:
12     print("退学吧")

 1 #比较三个数的大小
 2 
 3 max_number = 0
 4 number1 = int(input("number1="))
 5 number2 = int(input("number2="))
 6 number3 = int(input("number3="))
 7 if number1 > number2:
 8     max_number = number1
 9     if max_number > number3:
10         print("最大值为：",max_number)
11     else:
12         max_number = number3
13         print("最大值为：",max_number)
14 else:
15     max_number = number2
16     if max_number > number3:
17         print("最大值为：",max_number)
18     else:
19         max_number = number3
20         print("最大值为：",max_number)

name=['xp','qa','ws','ed']
x=0
for x in name:
    print(x)

xp
qa
ws
ed

sum=0
x=1
for x in range(101):    # range() 函数生成（0，100）整数序列
    sum=sum+x          #这里一定要注意缩进
    print(sum)

list_number=list(range(5))
print(list_number)

[0,1,2,3,4]

1 for i in range(1,101,2):
2     if i % 2 ==1:
3         print("loop:",i)

for i in range(1,101,2):
        print("loop:",i)

 1 n = 3
 2 user_name = "li"
 3 pass_name = "123456"
 4 while n>0:
 5     name = input("请输入用户名：")
 6     password=input("请输入用户名密码：")
 7     if name == user_name and password == pass_name:
 8         print("欢迎进入....")
 9         break
10     else:
11         n=n-1
12     if n==0:
13         print("该用户名被锁定")
14     else:
15         print("密码输入错误，还有", n, "次机会")

 1 _user = "li"
 2 _passwd = '123'
 3 counter = 0
 4 while counter <3:
 5     username = input("Username:")
 6     password = input("Passworld:")
 7     if username == _user and password == _passwd:
 8         print("Welcome %s login...."%_user)
 9         break
10     else:
11         print("Invalid username or password!")
12     counter += 1
13 else:
14     print("你行不行啊")

 1 _user_name = "xp"
 2 _user_password = "12345"
 3 for i in range(3):
 4     user_name = input("User_name:")
 5     user_password = input("User_password:")
 6     if user_name == _user_name and user_password == _user_password:
 7         print("Welcome login....")
 8         break
 9     else:
10         print("Invalid username or password!")

1 #打印1~100之内的偶数部分
2 even_number = 1
3 while even_number <= 100:
4     even_number +=1
5     if even_number % 2 == 0:
6         print(even_number)