擅长:python、mysql、java
<p>尝试<code>stack</code>+<code>reset_index</code></p>
<pre><code>df_new = df.stack().reset_index()
df_new[["level_0", "level_1"]] = df_new[["level_0", "level_1"]].astype(int) + 1
df_new
level_0 level_1 0
0 1 1 A11
1 1 2 A12
2 2 1 A21
3 2 2 A22
4 3 1 A31
5 3 2 A32
</code></pre>
<p><code>df.stack()</code>给出了一个多索引序列</p>
^{pr2}$