擅长:python、mysql、java
<p>只需沿轴1应用<code>min</code>函数。</p>
<pre><code>In [1]: import pandas as pd
In [2]: df = pd.read_csv('test.cvs', parse_dates=['d1', 'd2', 'd3'])
In [3]: df.ix[2, 'd1'] = None
In [4]: df.ix[1, 'd2'] = None
In [5]: df.ix[4, 'd3'] = None
In [6]: df
Out[6]:
d1 d2 d3
0 2013-02-07 00:00:00 2013-03-08 00:00:00 2013-05-21 00:00:00
1 2013-02-07 00:00:00 NaT 2013-05-21 00:00:00
2 NaT 2013-03-02 00:00:00 2013-05-21 00:00:00
3 2013-02-04 00:00:00 2013-03-08 00:00:00 2013-01-04 00:00:00
4 2013-02-01 00:00:00 2013-03-06 00:00:00 NaT
In [7]: df.min(axis=1)
Out[7]:
0 2013-02-07 00:00:00
1 2013-02-07 00:00:00
2 2013-03-02 00:00:00
3 2013-01-04 00:00:00
4 2013-02-01 00:00:00
dtype: datetime64[ns]
</code></pre>