date_joins.r

library(lubridate)
library(dplyr)

#fake data as an example, just 4 ranodm dates in the last month
set.seed(123)
fake_data_a <- data.frame(date = today() - sample(30,4), value_a=rnorm(4))
fake_data_b <- data.frame(date = today() - sample(30,4), value_b=rnorm(4))

#find all the dates in the window dfeine by fake_data_a
all_dates <- data.frame(date = seq(min(fake_data_a$date), max(fake_data_a$date), by=1))

#join up both tables, `reduce` here is just 'keep calling left join'
all_dates_both_values <- purrr::reduce(list(all_dates, fake_data_a, fake_data_b) , left_join, by="date")