擅长:python、mysql、java
<p>使用:</p>
<pre><code>print (df)
Product_id month sales
0 1 01-2018 25
1 1 02-2018 34
2 1 06-2018 29 <- changed dates
3 1 04-2018 45
4 2 02-2018 3
5 2 04-2018 2
df['month'] = pd.to_datetime(df['month'])
df = (df.set_index(['month','Product_id'])['sales']
.unstack(fill_value=0)
.asfreq('MS', fill_value=0)
.unstack()
.reset_index(name='value'))
print (df)
Product_id month value
0 1 2018-01-01 25
1 1 2018-02-01 34
2 1 2018-03-01 0
3 1 2018-04-01 45
4 1 2018-05-01 0
5 1 2018-06-01 29
6 2 2018-01-01 0
7 2 2018-02-01 3
8 2 2018-03-01 0
9 2 2018-04-01 2
10 2 2018-05-01 0
11 2 2018-06-01 0
</code></pre>