运算符

1. 基本运算符

1. 算术运算符
 + - * /   % ** //

2. 比较运算符
	== != > < >= <=

3. 赋值运算符 =

4. 增量赋值

n = 666
n = n + 1  # n += 100
n = n - 1  # n -= 1
n = n * 1  # n *= 1
n = n / 1  # n /= 1
print(n)  # 667
5. 链式赋值
x = 10
y = 10
z = 10
print(x, y ,z)

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

6. 交叉赋值
# 交换m，n的值
# m = n
# n = m
# print(m, n)
# 借助于第三个变量
# temp = m
# m = n
# n = temp
# print(m, n)

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

7. 解压赋值
# l, l1, l2, l3 = names_list
# l, l1, l2, l3 = ['kevin', 'jack', 'rose', 'tank', ]
# print(l, l1, l2, l3)

# l, *_, l3 = ['kevin', 'jack', 'rose', 'tank', ]
# print(l)
# print(l3)
# '''
#     *后面的变量名结束多余的变量值，并且组装成列表的形式返回
# '''
# print(_)  # ['jack', 'rose']

# l, *_, last = ['kevin', 'jack', 'rose', 'tank', ]
# print(last)

8. 逻辑运算符
    and:与，连接两个条件，它的结果两边必须都是真，结果才是真
       	>>>: 2 > 1 and 1 != 1 and True and 3 > 2
            False
            
    or：或，连接的两个条件，只要有一个是真，结果就是真
    	>>>:2 > 1 or 1 != 1 or True or 3 > 2
             True
            
    not：非，取反
    	    >>>:  (3>4 and 4>3) or (1==3 and 'x' == 'x') or 3 >3
    True 
    not True--->False
    # 优先级not>and>or

2. 成员运算符

关键字：in(在)  not in(不在)
names_list = ['kevin', 'jack', 'tank', 'tony']
print('kevin' in names_list)  # True  False
print('aa' in names_list)
print('bb' not in names_list)

print('hello' in 'hellworld')
print('ke' in 'kevin')

print('kevin' in {'username': 'kevin', 'age': 18})  # False
print('username' in {'username': 'kevin', 'age': 18})  # False

'''字段暴露给外界的是K'''

3. 身份运算符

# 比较两个值是否相等
关键字：==(比较的是值是否相等) 	is(比较的是内存地址是否相等)
s1 = ['kevin', 'tank', 'jack']
s2 = ['kevin', 'tank', 'jack']

print(s1 == s2)  # True
# is比较的是id
print(id(s1))
print(id(s2))

print(s1 is s2)  # False

"""
值相等的内存地址不一定相等
内存地址相等的值一定相等
"""