day04 运算符 流程控制 （if while/of）

1. 运算符
算数运算符

+ - * /

int / float :数字类型

# print(10 + 3.1)
# print(10 / 3)
# print(10 // 3)
# print(10 % 3)
# print(10 ** 2)

赋值运算符

增量赋值

age=18

age=age+1

print=(age) #19

age+=1

print(gae)#19

交叉赋值

x=18  y=22

x,y=22,18

print(x,y) # 22,18

链式赋值

x=y=z=10

print(x,y,z) #10,10,10

解压赋值

列表的解压赋值

# salaries=[1.1,2.2,3.3,4.4,5.5]
# a,b,_,_,_=salaries
# a,b,*_=salaries
# *_,a,b=salaries
# a,*_,b=salaries
# print(a,b,)

2. 字典的解压赋值

 dic={'aaa':1,'bbb':2,'ccc':3}
# x,y,z=dic
# print(x,y,z)

逻辑运算符

and or not

# and: 左右两个条件必须同时成立，最终结果才为True
# print(10 < 3 and 3 == 3)

# or: 左右两个条件只要有一个成立，最终结果就为True
# print(10 < 3 or 3 == 3)
# print(10 < 3 or 3 < 3)

# not:将紧跟其后的条件结果取反
# print(not 10 > 3)
# print(not 10 < 3 or 3 < 3)

# res=(10 > 3 and 3 == 1) or ((4 < 3 and True) or (not 1 > 2 or 3 > 2))

# print(res)

比较运算符

# ==
# print(10 != 3)

# 了解
# msg1='abcdef'
# msg2='abcz'

# print(msg2 > msg1)

l1=[1,'aaa',333]
l2=[2,'b']
print(l2 > l1)

2. 流程控制
if

语法一:
# if 条件:
#     代码1
#     代码2
#     代码3

# gender='female'
# age=18
# is_beautiful=True
#
# if gender == 'female' and age > 16 and age < 20 and is_beautiful:
#     print('开始表白。。。。')
#
# print('其他代码')

#语法二:
# if 条件:
#     代码1
#     代码2
#     代码3
# else:
#     代码1
#     代码2
#     代码3

# gender='female'
# age=26
# is_beautiful=True
#
# if gender == 'female' and age > 16 and age < 20 and is_beautiful:
#     print('开始表白。。。。')
# else:
#     print('阿姨好')
#
# print('其他代码')

#语法三:
# if 条件1:
#     if 条件2:
#         代码1
#         代码2
#         代码3

# gender='female'
# age=18
# is_beautiful=True
# is_successfull=True
#
# if gender == 'female' and age > 16 and age < 20 and is_beautiful:
#     print('开始表白。。。。')
#     if is_successfull:
#         print('在一起，，，')
#     else:
#         print('逗你玩呢。。。')
# else:
#     print('阿姨好')
#
# print('其他代码')
#

#语法四:
# if 条件1:
#     代码1
#     代码2
#     代码3
# elif 条件2:
#     代码1
#     代码2
#     代码3
# elif 条件3:
#     代码1
#     代码2
#     代码3
# .......
# else:
#     代码1
#     代码2
#     代码3

'''
如果：成绩>=90，那么：优秀

如果成绩>=80且<90,那么：良好

如果成绩>=70且<80,那么：普通

其他情况：很差
'''

score=input('your score: ')
score=int(score)

if score >= 90:
    print('优秀')
elif score >= 80:
    print('良好')
elif score >= 70:
    print('普通')
else:
    print('很差')

循环（while/for）

 引入：
# name='egon'
# pwd='123'
#
# inp_name=input('your name: ')
# inp_pwd=input('your password: ')
# if inp_name == name and inp_pwd == pwd:
#     print('login successfull')
# else:
#     print('name or password error')
#
# inp_name=input('your name: ')
# inp_pwd=input('your password: ')
# if inp_name == name and inp_pwd == pwd:
#     print('login successfull')
# else:
#     print('name or password error')
#
# inp_name=input('your name: ')
# inp_pwd=input('your password: ')
# if inp_name == name and inp_pwd == pwd:
#     print('login successfull')
# else:
#     print('name or password error')
#
#循环就是重复做某件事
# 语法：
# while 条件:
#     代码1
#     代码2
#     代码3

# while True:
#     1+1

# n=1
# while n < 10:
#     print(n)
#     n+=1

# name='egon'
# pwd='123'
#
# tag=True
# while tag:
#     inp_name=input('your name: ')
#     inp_pwd=input('your password: ')
#     if inp_name == name and inp_pwd == pwd:
#         print('login successfull')
#         tag=False
#     else:
#         print('name or password error')

# while+break:终止本层循环
name='egon'
pwd='123'

while True:
    inp_name=input('your name: ')
    inp_pwd=input('your password: ')
    if inp_name == name and inp_pwd == pwd:
        print('login successfull')
        break
    else:
        print('name or password error')