<p><code>last_valid_index</code>+<code>agg('last')</code></p>
<pre><code>A=data.iloc[:,2:].apply(lambda x : x.last_valid_index(),1)
B=data.groupby(['value'] * data.shape[1], 1).agg('last')
data['date']=A
data['obs']=B
data
Out[1326]:
field1 field2 2014 2015 2016 2017 date obs
0 a 0.0 1.0 2.0 3.0 4.0 2017 4.0
1 b 5.0 6.0 7.0 NaN NaN 2015 7.0
2 c 10.0 11.0 12.0 NaN NaN 2015 12.0
3 d 15.0 16.0 17.0 NaN NaN 2015 17.0
4 e 20.0 21.0 NaN NaN NaN 2014 21.0
5 f 25.0 26.0 27.0 28.0 29.0 2017 29.0
6 g 30.0 31.0 32.0 33.0 34.0 2017 34.0
</code></pre>
<hr/>
<p>通过使用<code>assign</code>我们可以把它们作为一个打击推到一条线上</p>
<pre><code>data.assign(date=data.iloc[:,2:].apply(lambda x : x.last_valid_index(),1),obs=data.groupby(['value'] * data.shape[1], 1).agg('last'))
Out[1340]:
field1 field2 2014 2015 2016 2017 date obs
0 a 0.0 1.0 2.0 3.0 4.0 2017 4.0
1 b 5.0 6.0 7.0 NaN NaN 2015 7.0
2 c 10.0 11.0 12.0 NaN NaN 2015 12.0
3 d 15.0 16.0 17.0 NaN NaN 2015 17.0
4 e 20.0 21.0 NaN NaN NaN 2014 21.0
5 f 25.0 26.0 27.0 28.0 29.0 2017 29.0
6 g 30.0 31.0 32.0 33.0 34.0 2017 34.0
</code></pre>