擅长:python、mysql、java
<p>另一个解决方案重写为:</p>
<p>使用<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.mul.html" rel="nofollow noreferrer">^{<cd1>}</a>,<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.sub.html" rel="nofollow noreferrer">^{<cd2>}</a>,
<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.div.html" rel="nofollow noreferrer">^{<cd3>}</a>和<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.sum.html" rel="nofollow noreferrer">^{<cd4>}</a>,对于<code>length</code>的<code>DataFrame</code>最快的是<code>len(df.index)</code></p>
<pre><code>df['c'] = df.a.mul(len(df.index)).sub(df.a.sum()).div(df.b)
print (df)
a b c
0 11 100 0.10
1 2 100 -0.17
2 10 100 0.07
</code></pre>
<p>它起作用了,因为:</p>
<pre><code>((11-2) + (11-10))
</code></pre>
<p>同:</p>
<pre><code>(2 * 11) - (2 + 10)
</code></pre>
<p>同:</p>
<pre><code>(3 * 11) - (2 + 10 + 11)
</code></pre>