擅长:python、mysql、java
<p><code>handle</code>不返回任何内容,因此<code>harry</code>将是<code>NoneType</code>。
分两次执行:首先分配实例,然后调用方法:</p>
<pre><code>>>> class tool:
... def hello(self,name):
... self.name="hello "+name
...
>>> a=tool()
>>> a.hello('i')
>>> a.name
'hello i'
>>> b=tool().hello('b')
>>> b.name
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'name'
>>> type(b)
<type 'NoneType'>
</code></pre>