a = 10

b = 20

list = [1,2,3,4,5]

print(a in list)

print(b not in list)

a = 20

print(a in list)

print(a is b)

print('*'*20)

c = 'c'

d = 'c'

print(c is d) # True 这个是个变量缓存的概念

c = 'c'*10000

d = 'c'*10000

print(c is d) # False 字符串太长就不一致的

print(c==d) # True 这个值就是相等的了