擅长:python、mysql、java
<p>如果你真的想这么做,这个链接提供了一个非常酷的方法来实现。唯一的警告是必须使用eval/exec/execfile执行代码。在</p>
<p><a href="https://mail.python.org/pipermail/python-ideas/2011-March/009657.html" rel="nofollow">https://mail.python.org/pipermail/python-ideas/2011-March/009657.html</a></p>
<pre><code>class MyDict:
def __init__(self, mapping):
self.mapping = mapping
def __getitem__(self, key):
value = self.mapping[key]
if hasattr(value, '__get__'):
print('Invoking descriptor on', key)
return value.__get__(key)
print('Getting', key)
return value
def __setitem__(self, key, value):
self.mapping[key] = value
class Property:
def __init__(self, getter):
self.getter = getter
def __get__(self, key):
return self.getter(key)
if __name__ == '__main__':
md = MyDict({})
md['x'] = 10
md['_y'] = 20
md['y'] = Property(lambda key: md['_'+key])
print(eval('x+y+1', {}, md))
</code></pre>
<p>虽然有点笨重,但我觉得这很酷。在</p>