擅长:python、mysql、java
<p>使用<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.melt.html" rel="nofollow noreferrer">^{<cd1>}</a>和聚合<code>sum</code>:</p>
<pre><code>s = df.melt('v').groupby('value')['v'].sum()
print (s)
value
Africa 1
Asia 5
Europe 6
North America 10
Name: v, dtype: int64
</code></pre>
<p>对于<code>DataFrame</code>:</p>
<pre><code>df = df.melt('v', value_name='a').groupby('a', as_index=False)['v'].sum()
print (df)
a v
0 Africa 1
1 Asia 5
2 Europe 6
3 North America 10
</code></pre>