擅长:python、mysql、java
<p>使用python3,您可以使用Python食谱中所写的<a href="https://github.com/dabeaz/python-cookbook/blob/master/src/9/multiple_dispatch_with_function_annotations/example1.py" rel="noreferrer">Implementing Multiple Dispatch with Function Annotations</a>:</p>
<pre><code>import time
class Date(metaclass=MultipleMeta):
def __init__(self, year:int, month:int, day:int):
self.year = year
self.month = month
self.day = day
def __init__(self):
t = time.localtime()
self.__init__(t.tm_year, t.tm_mon, t.tm_mday)
</code></pre>
<p>它的工作原理如下:</p>
<pre><code>>>> d = Date(2012, 12, 21)
>>> d.year
2012
>>> e = Date()
>>> e.year
2018
</code></pre>