Get index of row by value in column
<p>I have the following dataframe:</p>

<pre><code>     date         value
0    2016-01-01   gfhgh
1    2016-01-02   acgb
2    2016-01-03   yjhgs
</code></pre>

<p>I need to get the index of a row where date is a predefined value. For example for 2016-01-02, I need to get 1. Each date will be unique.</p>