擅长:python、mysql、java
<p>使用<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.mask.html" rel="nofollow noreferrer">^{<cd1>}</a>或<a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.where.html" rel="nofollow noreferrer">^{<cd2>}</a>可以很好地处理重复索引:</p>
<pre><code>#create duplicated indices for test
df.index = [0,0]
print (df)
city_reg city_live reg_region live_region
0 Moscow Tver 77 69
0 Tambov Tumen' 86 86
df['city_reg'] = df['city_reg'].mask(df.reg_region == df.live_region, df['city_live'])
</code></pre>
<p>或:</p>
<pre><code>df['city_reg'] = np.where(df.reg_region == df.live_region, df['city_reg'], df['city_live'])
</code></pre>
<hr/>
<pre><code>print (df)
city_reg city_live reg_region live_region
0 Moscow Tver 77 69
0 Tumen' Tumen' 86 86
</code></pre>