is 和 == 的区别

== 是比较两个变量的值，如果值相同，就会返回True，否则返回False

is 是比较两个变量的内存地址，如果内存地址相同，返回True，否则返回False

>>> a = [1, 2, 3]
>>> b = [1, 2, 3]
>>> a == b
True
>>> a is b
False
>>> id(a)
4505566728
>>> id(b)
4504821192
>>> x = [2, 3, 4]
>>> y = x
>>> x == y
True
>>> x is y
True
>>> id(x)
4505231880
>>> id(y)
4505231880