擅长:python、mysql、java
<pre><code>def combine_lists(list1, list2):
# Generate a new list containing the elements of list2
# Followed by the elements of list1 in reverse order
buf = list2[:] # or list2.copy()
buf.extend(reversed(list1))
return buf
Jamies_list = ["Alice", "Cindy", "Bobby", "Jan", "Peter"]
Drews_list = ["Mike", "Carol", "Greg", "Marcia"]
print(combine_lists(Jamies_list, Drews_list))
</code></pre>
<p>list的<code>extend</code>方法修改当前列表,但不返回任何内容,因此您的表达式:<code>list3=list2.extend(list1.reverse())</code>assign to <code>list3</code>value<code>None</code></p>
<p>关于<code>reverse</code>也一样。它修改当前列表,但返回<code>None</code>。您可以用<code>reverse(list)</code>方法替换它</p>