运算符和用户交互

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1 运算符

1.1 算术运算符

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print(10 + 12)
print(type(10 + 3.3))
print(10 / 3)
print(10 // 3)
print(10 % 3)
print(10 ** 2)

了解：
print("abc" + "ddd")
print("abc" * 3)

print([1,2,3]+[4,5,6])
print([1,2,3]*3)

1.2 比较运算

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l1 = [1,2,3]
l2 = [1,2,3]
print(l1 == l2)  # 值相等==的结果就成立
print(id(l1))
print(id(l2))
print(l1 is l2)  # id一样is的结果才为True

res1 = True
res2 = 10 > 3
res3 = 11 == 11
print(res1,id(res1))
print(res2,id(res2))
print(res3,id(res3))

tag = 123
print(tag is None)

print(10 != 11)
print(10 >= 11)

1.3 赋值运算符

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age = 18

1.3.1 增量赋值

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age += 3  # age = age + 3
age /= 3  # age = age / 3
print(age)

1.3.2 链式赋值

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x=10
y=x
z=y
x=y=z=10

1.3.3 交叉赋值

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m = 100
n = 200

temp=m
m=n
n=temp
m,n=n,m
print(m)
print(n)

1.3.4 解压赋值

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salaries = [1.1,2.2,3.3,4.4,5.5]
mon0 = salaries[0]
mon1 = salaries[1]
mon2 = salaries[2]
mon3 = salaries[3]
mon4 = salaries[4]
mon0,mon1,mon2,mon3,mon4=salaries
mon0,mon1,mon2,mon3,mon4,mon5=salaries  # 报错
mon0,mon1,mon2,mon3=salaries  # 报错
print(mon0,mon1,mon2,mon3,mon4)

mon0,mon1,*_=salaries
print(mon0)
print(mon1)
print(_)

mon0,mon1,*_,mon_last=salaries
print(mon0)
print(mon1)
print(mon_last)

1.4 逻辑运算符

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# not: 把紧跟其后的那个条件取反
# print(not True)
# print(not 10 > 3)
# print(not 1)
# print(not 0)

# and：连接左右两个条件,两个条件必须都为True，最终结果才为True
# print(10 > 3 and 1 == 1)
# print(10 > 3 and 1 == 1 and 3 < 2 and 1 > 0)

# or:连接左右两个条件,但凡有一个条件为True，最终结果就为True
# print(10 < 3 or “egon” == “egon”)
# print(10 > 3 or 1 == 1 or 3 < 2 or 1 > 0)

# print(3>4 and 4>3 or not 1==3 and ‘x’ == ‘x’ or 3 >3 and not ‘egon’ != “egon” or 1 > 0)
# (3>4 and 4>3) or (not 1==3 and ‘x’ == ‘x’) or (3 >3 and not ‘egon’ != “egon”) or 1 > 0
# 3>4 and (4>3 or not 1==3) and ‘x’ == ‘x’ or 3 >3 and not (‘egon’ != “egon” or 1 > 0)

# print(1 and 3)

# print(1 and 3 or 4)

# (1 and 3) or 4

2 用户交互

input函数

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# 控制计算机能够像人一样接收外界输入的内容
name = input(“请输入你的账号：”) # “[1,2,3]”
print(name,type(name))
print(name == “egon”)

age = input(“请输入你的年龄：”) # age=”19”
age=int(age)
print(age > 18) # “19” > 18
"""请输入您的用户名
请输入您的密码
判断 输入的用户名 等于 正确的用户名 并且 输入的密码 等于 正确的密码:
告诉用户登录成功
否则:
告诉用户账号密码错误
"""