<p>我在代码战中解决了一些kata,在当前的kata中,我试图得到一个元素在我设置为参数的列表中出现了多少次,然后用它作为for循环的范围</p>
<p>但是,当我调用函数时,它返回:</p>
<pre><code>File "<pyshell#8>", line 3, in delete_nth
if order.count(item) > max_e:
AttributeError: 'NoneType' object has no attribute 'count'
</code></pre>
<p>这是我的密码</p>
<pre class="lang-py prettyprint-override"><code>def delete_nth(order,max_e):
for item in order:
if order.count(item) > max_e:
for i in range(order.count(item) - max_e):
order = order.remove(item)
return order
l = [20,37,20,21]
delete_nth(l,1) #except [20,37,21]
</code></pre>