<p>使用<code>resample</code>+<code>first</code>/<code>last</code>/<code>min</code>/<code>max</code>:</p>
<pre><code>df.set_index('Day').resample('1D').first().fillna(0).reset_index()
Day Movie Rating
0 2017-01-01 GreatGatsby 5.0
1 2017-01-02 TopGun 5.0
2 2017-01-03 Deadpool 1.0
3 2017-01-04 0 0.0
4 2017-01-05 0 0.0
5 2017-01-06 0 0.0
6 2017-01-07 0 0.0
7 2017-01-08 0 0.0
8 2017-01-09 0 0.0
9 2017-01-10 PlanetOfApes 2.0
</code></pre>
<p>如果<code>Day</code>不是<code>datetime</code>列,请先使用<code>pd.to_datetime</code>对其进行转换:</p>
^{pr2}$
<hr/>
<p>文<code>asfreq</code>备选方案:</p>
<pre><code>df.set_index('Day').asfreq('D').fillna(0).reset_index()
Day Movie Rating
0 2017-01-01 GreatGatsby 5.0
1 2017-01-02 TopGun 5.0
2 2017-01-03 Deadpool 1.0
3 2017-01-04 0 0.0
4 2017-01-05 0 0.0
5 2017-01-06 0 0.0
6 2017-01-07 0 0.0
7 2017-01-08 0 0.0
8 2017-01-09 0 0.0
9 2017-01-10 PlanetOfApes 2.0
</code></pre>