I'd like to merge the two data sets by the date, keeping all the dates and filling in the totals col with NA when the date doesn't match
Data set 1
dates A_totals
2015-07-09 1
2015-07-10 1
2015-07-12 2
2015-07-14 4
2015-07-16 0
Data set 2
dates B_totals
2015-07-09 2
2015-07-11 5
2015-07-13 6
2015-07-15 9
2015-07-17 1
Desired Output
dates A_totals B_totals
2015-07-09 1 2
2015-07-10 1 NA
2015-07-11 NA 5
2015-07-12 2 NA
2015-07-13 NA 6
2015-07-14 4 NA
2015-07-15 NA 9
2015-07-16 0 NA
2015-07-17 NA 1