擅长:python、mysql、java
<p><strong>考虑重组数据</strong></p>
<p>除非您的<em>实</em>数据要求您重置为<code>MultiIndex</code>,否则在执行<code>groupby()</code>之前似乎没有必要重新编制索引。在</p>
<p>如果<code>groupby</code><code>C1</code>只有你得到你想要的示例输出:</p>
<pre><code>import pandas as pd
values = {'C1': ['B', 'A'],
'C2': ['B', 'A'],
'C3': ['B', 'A'],
}
df = pd.DataFrame(values)
print 'Original DataFrame'
print df
print
df2 = df.set_index(keys=['C1', 'C2'], inplace=False)
print 'Reindexed DataFrame'
print df2
print
grouped = df.groupby(['C1'], sort=False)
grouped2 = df2.groupby(level='C1', sort=False)
print 'Original Groups'
print grouped.groups
print
print 'Reindexed Groups'
print grouped2.groups
print
print 'Original Group for loop output'
for name, group in grouped:
print(name)
print
print 'Reindexed Group for loop output'
for name, group in grouped2:
print(name)
</code></pre>
<hr/>
^{pr2}$