面向对象编程(5) `__getitem__`、`__setitem__`、`__delitem__`

1,** __setitem__**

class Foo(object):

    def __setitem__(self, key, value):
        print(key, value)


obj = Foo()
obj["xxx"] = 123
# xxx 123

2,__getitem__

class Foo(object):

    def __setitem__(self, key, value):
        print(key, value)

    def __getitem__(self, item):
        print(item)


obj = Foo()
obj["ooo"]
# ooo

3，__delitem__

class Foo(object):

    def __setitem__(self, key, value):
        print(key, value)

    def __getitem__(self, item):
        print(item)

    def __delitem__(self, key):
        print(key)
obj = Foo()

del obj["ooo"]
# ooo