Pandas select closest date in past
<p>Being a beginner with <code>pandas</code>, I wonder how I can select the <em>closest</em> date in the past? E.g. I  have a <code>dataframe</code> as follows:</p>

<pre><code>               Terminart                        Info     Datum  Ergebnis
0       Hauptversammlung                         NaN  22.06.16       NaN
1        Jahresabschluss                        2015  10.03.16       NaN
2         Quartalszahlen                     Q3 2015  28.10.15       NaN
3         Quartalszahlen                     Q2 2015  29.07.15       NaN
4       Hauptversammlung                         NaN  05.05.15       NaN
5         Quartalszahlen                     Q1 2015  29.04.15       NaN
6  Bilanzpressekonferenz                        2014  12.03.15       NaN
7  Bilanzpressekonferenz  Jahrespressekonferenz 2015  12.03.15       NaN
</code></pre>

<p><hr>
I can select the <code>Terminart</code> with <code>df.loc()</code>, ie:</p>

<pre><code>df.loc[df['Terminart'] == 'Hauptversammlung']
</code></pre>

<p>selects only two rows (which is correct).<br>
<hr>
However, how can I select the <em>closest date</em> in the past? It would be the first row (<code>06/22/16</code>) here? The dataframe is not ordered by default.</p>