数组
# 用魔法方法实现一个数组
class Array:
def __init__(self,size=30):
self._size = size
self._items = [None] * size
def __getitem__(self,index):
return self._items[index]
def __setitem__(self,index,value):
self._items[index] = value
def __len__(self):
return self._size
def clear(self,value= None):
for i in range(len(self._items)):
self._items[i] = value
def __iter__(self):
for item in self._items:
yield item
def test_array():
size = 10
a = Array(size)
a[0] =1
assert a[0] ==1
print(a[0])
a.clear()
assert a[0] is None
test_array()