Date NewArea.km2 IDday
1 2018-03-01 152.3972 0
2 2018-03-15 152.3972 0
3 2018-04-01 152.3972 0
4 2018-04-15 152.3972 0
5 2018-05-01 152.3972 0
6 2018-05-15 152.3972 0
7 2018-06-01 152.3972 0
8 2018-06-10 152.3972 0
9 2018-06-15 152.3972 0
10 2018-06-20 152.3972 0
11 2018-06-21 152.3972 1
12 2018-06-22 152.3972 3
13 2018-06-23 152.3972 4
14 2018-06-24 152.3972 6
15 2018-06-25 152.3972 6
16 2018-06-26 152.3972 16
17 2018-06-27 152.3972 22
18 2018-06-28 152.3972 22
19 2018-06-29 152.3972 24
20 2018-06-30 152.3972 24
21 2018-07-01 152.3972 27
Here's a subset of the data I have. As you may have eluded to from the title, I would like to add rows to my data frame such that missing dates are also included (i.e. 2018-03-02, 2018-03-03, etc.) The other two columns ideally would fill up with NA's such that the new row 2 would read
2 2018-03-02 NA NA