擅长:python、mysql、java
<p>使用<a href="https://docs.python.org/3.7/library/itertools.html#itertools.combinations_with_replacement" rel="nofollow noreferrer">^{<cd1>}</a>怎么样?你知道吗</p>
<pre class="lang-py prettyprint-override"><code>from itertools import combinations_with_replacement
a = ['a', 'b', 'c']
list(combinations_with_replacement(a, 2))
[(0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2)]
</code></pre>
<p>这将允许您执行以下操作:</p>
<pre class="lang-py prettyprint-override"><code>for i, j in combinations_with_replacement(range(len(a)), 2):
print(i, j)
0 0
0 1
0 2
1 1
1 2
2 2
</code></pre>