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    

>Solution :

With base R using merge

merge(df1, df2, "dates", all=T)
       dates A_totals B_totals
1 2015-07-09        1        2
2 2015-07-10        1       NA
3 2015-07-11       NA        5
4 2015-07-12        2       NA
5 2015-07-13       NA        6
6 2015-07-14        4       NA
7 2015-07-15       NA        9
8 2015-07-16        0       NA
9 2015-07-17       NA        1

Data

df1 <- structure(list(dates = c("2015-07-09", "2015-07-10", "2015-07-12",
"2015-07-14", "2015-07-16"), A_totals = c(1L, 1L, 2L, 4L, 0L)), class = "data.frame", row.names = c(NA,
-5L))

df2 <- structure(list(dates = c("2015-07-09", "2015-07-11", "2015-07-13",
"2015-07-15", "2015-07-17"), B_totals = c(2L, 5L, 6L, 9L, 1L)), class = "data.frame", row.names = c(NA,
-5L))