span class='kw'>=</span> <span class='st'>"id"</span>)</div><div class='output co'>#&gt; <span class='message'>pad applied on the interval: month</span></div><div class='output co'>#&gt;       dt_var id val
#&gt; 1 2017-01-01  1   0
#&gt; 2 2017-02-01  1  NA
#&gt; 3 2017-03-01  1   1
#&gt; 4 2017-04-01  1  NA
#&gt; 5 2017-05-01  1   0
#&gt; 6 2017-01-01  2   0
#&gt; 7 2017-02-01  2  -1
#&gt; 8 2017-03-01  2  NA
#&gt; 9 2017-04-01  2   1</div><div class='input'><span class='co'># applying pad with do, interv