<p>您可以创建帮助数据框</p>
<pre><code>df=pd.DataFrame({'transaction_dt':pd.date_range('2014-01-06',periods = 35,freq='D')})
df.merge(df1,how='left').ffill()
Out[879]:
transaction_dt id units measure
0 2014-01-06 1.0 30.0 30.5
1 2014-01-07 1.0 30.0 30.5
2 2014-01-08 1.0 30.0 30.5
3 2014-01-09 1.0 30.0 30.5
4 2014-01-10 1.0 30.0 30.5
5 2014-01-11 1.0 30.0 30.5
6 2014-01-12 1.0 30.0 30.5
7 2014-01-13 1.0 30.0 30.5
8 2014-01-14 1.0 30.0 30.5
9 2014-01-15 1.0 30.0 30.5
10 2014-01-16 1.0 30.0 30.5
11 2014-01-17 1.0 30.0 30.5
12 2014-01-18 1.0 30.0 30.5
13 2014-01-19 1.0 30.0 30.5
14 2014-01-20 1.0 30.0 30.5
15 2014-01-21 1.0 30.0 30.5
16 2014-01-22 1.0 30.0 30.5
17 2014-01-23 1.0 30.0 30.5
18 2014-01-24 1.0 30.0 30.5
19 2014-01-25 1.0 30.0 30.5
20 2014-01-26 1.0 30.0 30.5
21 2014-01-27 1.0 30.0 30.5
22 2014-01-28 1.0 30.0 30.5
23 2014-01-29 1.0 30.0 30.5
24 2014-01-30 1.0 30.0 30.5
25 2014-01-31 1.0 30.0 30.5
26 2014-02-01 1.0 30.0 30.5
27 2014-02-02 1.0 30.0 30.5
28 2014-02-03 1.0 30.0 30.5
29 2014-02-04 1.0 5.0 22.6
30 2014-02-05 1.0 5.0 22.6
31 2014-02-06 1.0 5.0 22.6
32 2014-02-07 1.0 5.0 22.6
33 2014-02-08 1.0 5.0 22.6
34 2014-02-09 1.0 5.0 22.6
</code></pre>